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Hormone Concentrations (hormone + concentration)
Kinds of Hormone Concentrations Selected AbstractsPlasma Thyroid Hormone Concentrations in Dogs Competing in a Long-Distance Sled Dog RaceJOURNAL OF VETERINARY INTERNAL MEDICINE, Issue 4 2003David L. Panciera Plasma thyroxine (T4), 3,5,3,-triiodothyronine (T3), total protein, and albumin concentrations were measured in 15 dogs both before and after completion, and in an additional 16 dogs before and 24 dogs after completion, of a long-distance sled dog race. The plasma T4 concentration (mean ± SD) decreased significantly from 18.2 ± 5.4 nmol/L before to 14.3 ± 3.5 nmol/L after the race in dogs evaluated at both times and decreased significantly from 21.8 ± 10.5 nmol/L before to 15.8 ± 4.9 nmol/L after the race in dogs sampled only before or only after the race. The mean plasma T3 concentrations in dogs measured twice decreased significantly from 1.20 ± 0.48 nmol/L before to 0.74 ± 0.42 nmol/L after the race, as well as in dogs measured either before (1.28 ± 0.36 nmol/L) or after (0.69 ± 0.28 nmol/L) the race, respectively. Plasma total protein and albumin concentrations decreased significantly after completion of the race. No significant change was noted in 4 control dogs that did not compete in the race and were tested during a similar time period. The plasma concentrations of T4 and T3 were lower than the normal reference range established for this laboratory in 23 and 39%, respectively, of Alaskan sled dogs tested before the race. Plasma thyroid hormone concentrations frequently are below normal in conditioned Alaskan sled dogs and are further reduced after prolonged submaximal exercise. [source] A Study on the Occurrence of Polyovular Follicles in Porcine Ovaries with Particular Reference to Intrafollicular Hormone Concentrations, Quality of Oocytes and their in vitro FertilizationANATOMIA, HISTOLOGIA, EMBRYOLOGIA, Issue 3 2009T. Stankiewicz Summary The aim of this study was to identify the occurrence of polyovular follicles in porcine ovaries. We investigated the presence of such follicles in relation to age, and compared the intrafollicular concentrations of steroid hormones between poly- and uniovular follicles. Then we measured the size, viability and the in vitro fertilizing ability of the oocytes from polyovular follicles. Histological examinations documented the occurrence of polyovular follicles in pigs at various stages of follicular growth. Within antral follicles, the number of polyovular follicles was higher in the ovaries of gilts than in sows (P < 0.01). We noticed differences in the viability and size of oocytes recovered from the same follicles. We noted a higher concentration of oestradiol-17, and a lower concentration of progesterone in polyovular follicles as compared with uniovular follicles (P < 0.01). The amount of embryos after in vitro -fertilization of oocytes from polyovular follicles was significantly lower than that from uniovular ones. Nevertheless, we found that some oocytes from polyovular follicles also have the capacity to be fertilized in vitro and be developed to the blastocyst stage. [source] Growth, carcass composition and plasma growth hormone levels in cyclically fed rainbow troutJOURNAL OF FISH BIOLOGY, Issue 3 2006R. W. Blake Growth, body composition and plasma growth hormone levels were recorded weekly for 24 weeks in rainbow trout Oncorhynchus mykiss. Underyearling rainbow trout were individually identified using coded tags and placed on either a cyclic feeding regime of 3 weeks of deprivation followed by 3 weeks of feeding or a daily feeding regime. No significant difference was found in standard length and mass among the cyclically fed and daily fed fish at the end of the experiment. For cyclically fed fish, the absolute specific growth rate and condition factor reached a maximum during the last week of refeeding. Cyclically fed fish had a significantly higher moisture and protein content and lower lipid levels relative to fish fed daily. Absolute mass and fat loss in the deprivation phase of the feeding cycle decreased in intensity with subsequent feeding cycles, indicating that the fish were acclimatizing to the feeding regime. It was proposed that this response was an adaptation against possible adverse effects in the adults (e.g. locomotor performance, bone ossification rates, fat deposition rate, growth rate and age at sexual maturity). Plasma growth hormone concentrations were not affected by cyclic feeding indicating that variations in plasma growth hormone concentration are not the cause of compensatory growth in rainbow trout. [source] Hypothalamic Expression of Human Growth Hormone Induces Post-Pubertal Hypergonadotrophism in Male Transgenic Growth Retarded RatsJOURNAL OF NEUROENDOCRINOLOGY, Issue 10 2006J. S. Davies Growth hormone (GH) is known to regulate peripheral components of the hypothalamo-pituitary gonadal (HPG) axis, but it remains unclear whether GH exerts a significant influence on the activity of the hypothalamo-pituitary components of the HPG axis. In this study, we investigated the development of HPG axis function in the male transgenic growth retarded (Tgr) rat, a model of moderate systemic GH deficiency caused by hypothalamic expression of human (h)GH. Impaired postnatal somatotroph expansion and moderate GH deficiency in male Tgr rats were accompanied by a two- to three-fold increase in pituitary gonadotrophin content, but without a significant change in the pituitary gonadotroph population. A three- to nine-fold elevation in basal circulating luteinising hormone concentration was seen in postpubertal Tgr rats, with a smaller increase in follicle-stimulating hormone. Despite this hypergonadotrophism, there was no corresponding increase in steroidogenic (circulating testosterone and seminal vesicle weights) or gametogenic (spermatozoa counts in seminiferous tubules) activity in the postpubertal Tgr testis. Following puberty, the plasma leptin concentration also became progressively elevated in Tgr males. Circulating gonadotrophin and leptin levels were normalised in Tgr rats by peripheral physiological replacement of rat GH, but plasma testosterone concentration was unaffected. These results confirm that hGH exerts a positive influence on the central control of gonadotrophin secretion in the Tgr rat, but the absence of a corresponding elevation in the steroidogenic or gametogenic function of the Tgr testis implies that the peripheral GH/insulin-like growth factor I axis may also exert a permissive influence on testicular function. The relative contribution of somatogenic and lactogenic mechanisms and the potential influence of elevated leptin and decreased sensitivity to androgen feedback to the development of postpubertal hypergonadotrophism in Tgr males remain to be determined. [source] The effect of high ambient temperature on Ca, P and Mg balance and bone turnover in high-yielding dairy cowsANIMAL SCIENCE JOURNAL, Issue 4 2010Yuko KAMIYA ABSTRACT We investigated the effect of heat stress on Ca, P and Mg balance and bone turnover in lactating cows. In a 2 × 2 crossover design, four multiparous lactating Holstein cows were kept in a chamber and subjected to a constant moderate (18°C) ambient temperature (MT) or high (28°C) ambient temperature (HT). The cows were fed total mixed ration (Ca, 0.7%; P, 0.4%; Mg, 0.2%) ad libitum. The milk yield under HT (35.4 kg/day) tended to be lower (P < 0.10) than that under MT (43.2 kg/day). The concentrations of milk P (P < 0.05) and Mg (P < 0.01) were significantly lower under HT than MT. The Ca, P and Mg intake (P < 0.10); Ca (P < 0.10), P, and Mg (P < 0.05) secretion into milk; and Ca (P < 0.05), P (P < 0.01), and Mg (P < 0.05) absorption in the intestine were lower under HT than MT. The plasma osteocalcin, a marker of bone turnover, was significantly lower (P < 0.05) under HT than MT. Heat stress did not affect plasma C-telopeptide of collagen type I, a bone resorption marker, and plasma parathyroid hormone concentration. [source] Minimally invasive parathyroidectomy without intraoperative parathyroid hormone monitoring in patients with primary hyperparathyroidismBRITISH JOURNAL OF SURGERY (NOW INCLUDES EUROPEAN JOURNAL OF SURGERY), Issue 1 2007R. Mihai Background: Minimally invasive parathyroidectomy (MIP) is the preferred operation for patients with primary hyperparathyroidism (HPT) and positive preoperative imaging. This non-randomized case series assessed the long-term results of MIP performed without the use of intraoperative parathyroid hormone (ioPTH) monitoring. Methods: The study involved prospective collection of demographic, biochemical and operative details on a consecutive, unselected cohort of 298 patients who underwent surgery for non-familial primary HPT during a 5-year interval. The mean preoperative serum calcium level was 3·00 mmol/l with a mean parathyroid hormone concentration of 25·8 pmol/l. 99mTc-labelled sestamibi scanning and neck ultrasonography were performed in 262 patients. Results: Sestamibi scan showed unilateral uptake in 182 patients and a single parathyroid adenoma was confirmed on ultrasonography in 161 patients. MIP was performed in 150 patients. The mean duration of operation was 25 (range 8,65) min. Four patients needed conversion to conventional neck exploration. There was one postoperative haematoma and three cases of temporary recurrent laryngeal nerve neuropraxia. All but four patients were normocalcaemic after MIP. All the parathyroid tumours removed were adenomas, with a mean weight of 1·3 (range 0·1,17·4) g. No patient developed recurrent HPT after a median follow-up of 16 (range 3,48) months. Conclusion: The outcome of MIP without ioPTH monitoring was comparable to that reported in series that used ioPTH monitoring. Copyright © 2006 British Journal of Surgery Society Ltd. Published by John Wiley & Sons, Ltd. [source] Maternal thyroid hormone concentration during late gestation is associated with foetal position at birthCLINICAL ENDOCRINOLOGY, Issue 5 2009Hennie A. Wijnen Summary Objective, To evaluate whether there is an association between maternal thyroid hormone and foetal cephalic head position at term gestation. Context, Rotation and flexion of the head enables the foetus to negotiate the birth canal. Low-normal range thyroid hormone concentrations in euthyroid pregnant women constitute a risk of infant motor abnormality. We hypothesized that low normal maternal thyroid hormone levels are associated with increased risk of abnormal foetal position at delivery. Design, In 960 healthy Dutch women with term gestation and cephalic foetal presentation, thyroid parameters [foetal T4 (FT4), TSH and thyroid peroxidase antibody] were assessed at 36 weeks of gestation, and related to foetal head position (anterior cephalic vs. abnormal cephalic) and delivery mode (spontaneous vs. assisted delivery). Results, Women presenting in anterior position (n = 891) had significantly higher FT4 levels at 36 weeks of gestation than those with abnormal cephalic presentation (n = 69). There were no between-group differences for TSH. Regression analyses indicated that the risk of abnormal head position decreased as a function of increasing FT4 [single odds ratio (OR) = 0·87, 95% confidence intervals (CI) 0·77,0·98; multivariate OR = 0·88, 95% CI 0·72,0·99)]. A similar inverse relationship between maternal FT4 and risk of assisted delivery was obtained (OR = 0·86, 95% CI 0·79,0·95; OR = 0·91, 95% CI 0·84,0·98). Conclusion, The lower the maternal FT4 concentration at 36 weeks of gestation, the higher the risk of abnormal cephalic foetal presentation and assisted delivery. [source] The quantity of thyroid hormone in human milk is too low to influence plasma thyroid hormone levels in the very preterm infantCLINICAL ENDOCRINOLOGY, Issue 5 2002Aleid G. Van Wassenaer Summary background Thyroid hormone is crucial for brain development during foetal and neonatal life. In very preterm infants, transient low levels of plasma T4 and T3 are commonly found, a phenomenon referred to as transient hypothyroxinaemia of prematurity. We investigated whether breast milk is a substantial resource of thyroid hormone for very preterm neonates and can alleviate transient hypothyroxinaemia. Both the influence of breast feeding on plasma thyroid hormone levels and the thyroid hormone concentration in preterm human milk were studied. methods Two groups were formed from the placebo group of a randomized thyroxine supplementation trial in infants born at < 30 weeks' gestational age on the basis of the mean breast milk intake during the third, fourth and fifth weeks of life. One group received more than 50% breast milk (mean breast milk intake 84%, n = 32) and the other group less than 25% breast milk (mean breast milk intake 3·3%, n = 25). Plasma thyroid hormone concentrations were compared between the two groups. Breast milk was collected from mothers of infants participating in the same trial and the thyroxine concentration in breast milk was measured with RIA after extraction. results No significant differences were found between both groups in plasma concentrations of T4, free T4, T3, TSH, rT3 and thyroxine-binding globulin (TBG), which were measured once a week. Thyroxine concentration in breast milk ranged between 0·17 µg/l and 1·83 µg/l (mean 0·83, SD 0·3 µg/l) resulting in a maximum T4 supply of 0·3 µg/kg via ingested breast milk. In formula milk, the T4 concentration was equally low. Protease treatment did not influence the measured T4 concentrations. conclusions No differences in plasma thyroid hormone between breast milk-fed and formula-fed infants were found. The amount of T4 present in human milk and formula milk is too low to alter the hypothyroxinaemic state of preterm infants. [source] Pituitary and autonomic responses to cold exposures in manACTA PHYSIOLOGICA, Issue 4 2005J. Leppäluoto Abstract This review presents hormonal responses to various cold exposures and their calorigenic effects in man and some animals. Previous studies in rats have shown that cold exposures activate the hypothalamic-pituitary-thyroid axis. Increased thyroid hormone concentrations lead to heat production via general stimulation of metabolism (obligatory thermogenesis) and possibly via activation of thyroid hormone receptors and uncoupling protein 1 (UCP 1) and deiodinase enzyme genes in the brown adipose tissue (BAT). In human subjects long-term cold exposures do not seem to activate the pituitary-thyroid axis, but rather accelerate the elimination of triiodothyronine (T3), leading to low serum concentrations of free T3 hormone. In corollary to this a hypothyreotic condition with increased serum thyroid-stimulating hormone and impaired mood and cognitive performance can be observed after long-term cold exposures such as wintering. During cold exposures the sympathetic nerve system is activated and noradrenaline is released to blood circulation and to BAT, where it leads to production of cAMP, lipolysis and free fatty acids. Free fatty acids open the mitochondrial proton channel protein in BAT. Protons enter the mitochondria and inhibit ATP synthesis (uncoupling). By this way energy is transformed into heat (facultatory or adaptive thermogenesis). In adult human subjects the amount of BAT is small and adaptive thermogenesis (non-shivering thermogenesis) has a smaller role. UCP 1 with other uncoupling proteins may have other functions in the control of body weight, sugar balance and formation of reactive oxygen species. [source] Sorption of male hormones by soils and sedimentsENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 2 2007Il Kim Abstract ,This paper reports the sorption of two male hormones, testosterone and androstenedione, by four soil and sediment samples at both equilibrium and rate-limiting conditions. Unlike prior studies, androstenedione was studied independently of testosterone. Apparent sorption equilibrium is achieved in one to two weeks when the initial aqueous hormone concentrations (C0) at 10,000 ,g/L (,30% of their solubility limits [Sw]) and two to three weeks when the C0 is 300 ,g/L (less than 1% of Sw). The Freundlich model parameter n ranged from 0.698 to 0.899 for all soil,solute systems indicating nonlinear sorption isotherms. Isotherm nonlinearity leads to an inverse correlation between single-point organic carbon,normalized sorption distribution coefficients (KOC) and equilibrium androgen concentration (Ce). When Ce/Sw = 0.012, the log KOC values for testosterone and androstenedione on the various sorbents ranged from 6.18 to 6.75 and 6.83 to 6.04, respectively, compared to 6.30 to 6.80 and 6.16 to 6.92 when Ce/Sw = 0.004. This study suggests that male hormones may exhibit slow rates of sorption over 14 d or longer and that soils and sediments may have greater sorption distribution coefficients when concentrations fall into the ng/L range. [source] Effects of pre- and postnatal polychlorinated biphenyl exposure on metabolic rate and thyroid hormones of white-footed mice,ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 8 2001John B. French Jr. Abstract Energy budgets have proven to be a valuable tool for predicting life history from physiological data in terrestrial vertebrates, yet these concepts have not been applied to the physiological effects of contaminants. Contaminants might affect energy budgets by imposing an additional metabolic cost or by reducing the overall amount of energy taken in; either process will reduce the energy available for production (i.e., growth or reproduction). This study examined whole animal energetic effects of polychlorinated biphenyl (PCB) exposure in white-footed mice (Peromyscus leucopus). Exposure to PCBs is known to reduce concentrations of plasma thyroid hormones, and thyroid hormones exert strong control over the rate of energy metabolism in mammals. Peromyscus leucopus that were proven breeders were fed PCBs in their food at 0, 10, and 25 ppm. Through lactation, offspring were exposed to PCB from conception and were maintained on the maternal diet to adulthood. No effects were seen on energy metabolism (O2 consumption, measured in adulthood) or on growth, but there were large dose-dependent decreases in thyroid hormone concentrations, particularly T4. The apparent disparity in our data between unchanged metabolic rates and 50% reductions in T4 concentrations can be rationalized by noting that free T3 (the fraction not bound to plasma protein) in treated mice was not significantly different from controls and that metabolism is most strongly influenced by free T3. Overall, this study did not demonstrate any energetic consequences of PCB exposure in P. leucopus at dietary concentrations up to 25 ppm. [source] Effects of fungicides on thyroid function, metabolism, and thermoregulation in cotton rats,ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 8 2001Thomas E. Tomasi Abstract Among the myriad of recent studies on endocrine-disrupting chemicals, relatively few involve thyroid disruption, and most of these address exposure/disruption during embryonic life. Of those involving adult vertebrates, the endpoints examined are thyroid measurements. Even though thyroid disruption could potentially interfere with energy metabolism and thermoregulation such that over-winter survival might be compromised, the possible energetic consequences of these thyroid perturbations have not been investigated. We assessed thyroid function and measured resting metabolic rates of cotton rats chronically exposed to the fungicides vinclozolin or mancozeb. In addition, we measured norepinephrine-induced nonshivering thermogenesis and cold-induced thermogenesis and then cold-acclimated the mancozeb animals. Although thyroid hormone concentrations generally decreased, this was compensated for by an increase in thyroxine turnover (vinclozolin study only) such that thyroxine utilization rate was not different. In addition, there was no difference between the treated and control animals in any of the metabolic parameters measured. It is concluded that wild rodents exposed to these compounds are not energetically compromised. [source] Thyroid Function in Girls with Epilepsy with Carbamazepine, Oxcarbazepine, or Valproate Monotherapy and after Withdrawal of MedicationEPILEPSIA, Issue 3 2004Leena K. Vainionpää Summary: Purpose: Antiepileptic drugs may affect the serum thyroid hormone concentrations. The aim of this study was to evaluate thyroid function in 78 girls taking carbamazepine (CBZ), oxcarbazepine (OXC), or valproate (VPA) monotherapy for epilepsy and after withdrawal of the treatment. Methods: Forty-one girls taking VPA, 19 taking CBZ, and 18 taking OXC for epilepsy, as well as 54 healthy age-matched controls, aged 8 to 18 years, participated in the study. All the girls were examined clinically, and their pubertal stage was assessed. Blood samples were obtained for thyroid hormone and antibody assays. These examinations were repeated after a mean follow-up of 5.8 years to assess thyroid function, and 64 (82%) of 78 patients and 42 (78%) of 54 controls agreed to participate in the second evaluation. Results: In the first evaluation, the mean serum thyroid hormone concentrations were lower in the girls taking CBZ [thyroxine (T4), 70.2; SD, 10.9 nM; and free thyroxine (FT4), 11.5; SD, 1.8 pM] or OXC (T4, 74.9; SD, 16.4 nM; and FT4, 11.3; SD, 1.8 pM) than in the control girls (T4, 96.6; SD, 15.1 nM, and FT4, 14.4; SD, 1.5 pM; p < 0.001, all comparisons). However, thyrotropin (TSH) concentrations were normal in the girls taking CBZ or OXC. Sixty-three% of the girls taking CBZ and 67% of the girls taking OXC had serum T4 and/or FT4 levels below the lower limit of the reference range. The VPA-treated girls with epilepsy had normal serum T4 and FT4 concentrations, but slightly increased TSH levels (3.3; SD, 1.5 mU/L; p < 0.01) compared with the control girls (2.5; SD, 1.0 mU/L). Normal serum hormone concentrations were restored in the patients who discontinued the medication. Conclusions: Both CBZ and OXC reduce serum thyroid hormone concentrations in girls with epilepsy. Conversely, VPA is associated with normal serum thyroid hormone and increased thyrotropin levels. However, our results suggest that the changes in serum thyroid hormone and thyrotropin levels are reversible after withdrawal of the medication. [source] Thyroid hormone responses to endurance exerciseEQUINE VETERINARY JOURNAL, Issue S36 2006E. A. GRAVES Summary Reasons for performing study: Limited information exists about changes in circulating thyroid hormone concentrations during prolonged endurance exercise in horses. Objective: To examine the effects of prolonged exercise on serum iodothyronine concentrations in horses performing endurance exercise of varying distances. Methods: Serum concentrations of iodothyronines were measured in horses before and after completion of 40, 56, 80 and 160 km endurance rides (Study 1); daily during a 5 day, 424 km endurance ride (Study 2); and before and for 72 h after completion of a treadmill exercise test simulating a 60 km endurance ride (Study 3). Results: In Study 1, 40 and 56 km of endurance exercise had little effect on serum iodothyronine concentrations with the exception of a 10% decrease (P<0.05) in free thyroxine (FT4) concentration after the 56 km ride. In contrast, total thyroxine (T4), total triiodothyronine (T3), FT4 and free triiodothyronine (FT3) concentrations all decreased (P<0.05) after successful completion of 80 and 160 km rides, with decreases ranging from 13,31% and 47,54% for distances of 80 and 160 km, respectively. Further, pre-ride T4 concentration was lower (P<0.05) and FT3 concentration was higher (P<0.05) in horses competing 160 km as compared to horses competing over shorter distances. In Study 2, serum concentrations of T4, T3 and reverse triiodothyronine (rT3) progressively decreased (P<0.05) over the course of the multi-day ride. In Study 3, the greatest decrease (P<0.05) in all iodothyronines was observed at 12 h of recovery, ranging from 25% for FT4 to 53% for FT3, but all thyroid hormone concentrations had returned to the pre-exercise values by 24 h of recovery. Conclusion: Endurance exercise results in transient decreases in serum iodothyronine concentrations. Potential relevance: These data are important to consider when thyroid gland function is assessed by measurement of serum iodothyronine concentrations in endurance horses. [source] Saliva DHEA and cortisol responses following short-term corticosteroid intakeEUROPEAN JOURNAL OF CLINICAL INVESTIGATION, Issue 2 2010L. Jollin Eur J Clin Invest 2010; 40 (2): 183,186 Abstract Background, Given the high correlation between the serum and saliva hormone values demonstrated at rest, saliva provides a convenient non-invasive way to determine dehydroepiandrosterone (DHEA) and cortisol concentrations. However, to our knowledge, pituitary adrenal recovery following short-term suppression with corticosteroids has never been investigated in saliva. The aim of this study was therefore to examine how steroid hormone concentrations in saliva are influenced by short-term corticosteroid administration. Materials and methods, We studied saliva DHEA and cortisol concentrations before, during (day 1,day 7) and following (day 8,day 16) the administration of oral therapeutic doses of prednisone (50 mg daily for 1 week) in 11 healthy recreationally trained women. Results, Mean saliva DHEA and cortisol concentrations decreased immediately after the start of prednisone treatment (P < 0·05). Three days after concluding prednisone administration, both saliva DHEA and cortisol had returned to pretreatment levels. Conclusions, These data are consistent with previous studies on blood samples and suggest that non-invasive saliva samples may offer a practical approach to assessing pituitary-adrenal function continuously during and after short-term corticosteroid therapy. [source] The effect of sexual hormone abnormalities on proximal femur bone mineral density in hemodialysis patients and the possible role of RANKLHEMODIALYSIS INTERNATIONAL, Issue 1 2008Konstantinos K. DOUMOUCHTSIS Abstract Sexual hormone concentrations are commonly affected in chronic renal failure. The contribution of sex steroids to bone turnover regulation implies that sex steroid's dysfunction may be implicated in the emergence of renal osteodystrophy. This study was conducted to evaluate sex steroids and gonadotrophins in hemodialysis (HD) patients and to investigate their role in bone homeostasis in concert with other hormones and cytokines. Bone mineral density (BMD) at the proximal femur and intact parathyroid hormone (iPTH), osteoprotegerin, soluble receptor activator of NF-,B ligand (sRANKL), prolactin, total testosterone, estradiol, follicle-stimulating hormone (FSH), and luteinizing hormone (LH) were measured in serum samples in 42 patients, 21 men and 21 women, on maintenance HD therapy. Possible associations between clinical characteristics, biochemical parameters, and BMD values were investigated. In male HD patients, the testosterone concentration declined significantly with aging, whereas the estradiol level increased with longer duration of HD. Concurrently, testosterone correlated negatively with sRANKL concentrations (r=,0.520, p=0.016). Luteinizing hormone levels in male patients demonstrated statistically significant negative correlations with BMD values of the proximal femur. In the entire cohort of patients, FSH and LH were negatively associated with absolute values of proximal femur BMD. Gonadotrophin and sexual hormone concentrations in HD patients are associated with bone mineral status and consequently their derangements appear to contribute to the development of bone composition abnormalities in different types of renal osteodystrophy. Furthermore, testosterone's association with sRANKL levels in male HD patients suggests that RANKL may mediate the effect of testosterone on bone metabolism in these patients. [source] Endogenous sex hormones, prolactin and mammographic density in postmenopausal Norwegian womenINTERNATIONAL JOURNAL OF CANCER, Issue 11 2007Yngve Bremnes Abstract The associations between endogenous sex hormone levels and breast cancer risk in postmenopausal women are well established. Mammographic density is a strong risk factor for breast cancer, and possibly an intermediate marker. However, the results from studies on the associations between endogenous sex hormones and mammographic density are conflicting. The authors examined the associations between circulating levels of sex hormones, sex hormone binding globulin (SHBG) and prolactin and mammographic densities among postmenopausal women not currently using postmenopausal hormone therapy (HT). The authors also examined if insulin-like growth factor-I (IGF-I) levels influenced the association between estrogen and mammographic density. Altogether, 722 postmenopausal participants in the Norwegian governmental mammographic screening program had endogenous hormone concentrations measured. Mammograms were classified according to percent and absolute mammographic density using a previously validated computer-assisted method. After adjustment for age, number of children, age at menopause, body mass index and HT use, both plasma concentrations of SHBG (p -trend = 0.003) and estrone (p -trend = 0.07) were positively associated with percent mammographic density. When the analyses were stratified according to median IGF-I concentration, the weak association between estrone and mammographic density was strengthened among women with IGF-I levels below median, while the association disappeared among women with over median IGF-I levels (p for interaction = 0.02). In summary, the authors found a positive association between plasma SHBG levels and mammographic densities among 722 postmenopausal Norwegian women not currently using HT. Further, the authors found a positive but weak association between plasma estrone concentration and mammographic density, which appeared to be modified by IGF-I levels. © 2007 Wiley-Liss, Inc. [source] Dietary patterns, the Alternate Healthy Eating Index and plasma sex hormone concentrations in postmenopausal womenINTERNATIONAL JOURNAL OF CANCER, Issue 4 2007Teresa T. Fung Abstract To evaluate the association between overall diet and sex hormones concentrations, we collected blood from 578 postmenopausal women ages 43 and 69 years in 1989 or 1990. Food intake was measured in 1990 via a food frequency questionnaire. We calculated the Alternate Healthy Eating Index (AHEI), and dietary patterns were identified by factor analysis. The cross-sectional association between diet and estrogens, sex hormone binding globulin (SHBG) were evaluated with linear regression and adjusted for energy and other potential confounders. We found a higher AHEI score was associated with lower concentrations of estradiol, free estradiol, and higher concentrations of SHBG. The prudent pattern, with higher intakes of fruits, vegetables, and whole grains, was not associated with any sex hormones. The Western pattern, which represents higher intakes of red and processed meats, refined grains, sweets and desserts, was associated with a higher level of estradiol and lower concentrations of SHBG. Further adjustment for BMI attenuated these results except for free estradiol (5th vs. 1st quintile = 0.09 vs. 0.11 pg/mL, p for trend = 0.03). In addition, the AHEI was inversely associated with estradiol among those with BMI > 25, and Western pattern with SHBG among those with BMI < 25. In conclusion, we observed inverse associations between the AHEI score and several estrogens, and it was positively associated with plasma levels of SHBG. In contrast, the Western pattern was positively associated with estrogen levels and inversely with SHBG. However, these associations appeared to be largely accounted for by BMI. © 2007 Wiley-Liss, Inc. [source] Plasma cortisol and 11-ketotestosterone enzyme immunoassay (EIA) kit validation for three fish species: the orange clownfish Amphiprion percula, the orangefin anemonefish Amphiprion chrysopterus and the blacktip reef shark Carcharhinus melanopterusJOURNAL OF FISH BIOLOGY, Issue 3 2010S. C. Mills Commercially available enzyme immunoassay (EIA) kits were validated for measuring steroid hormone concentrations in blood plasma from three fish species: the orange clownfish Amphiprion percula, the orangefin anemonefish Amphiprion chrysopterus and the blacktip reef shark Carcharhinus melanopterus. A minimum of 5 µl plasma was required to estimate hormone concentrations with both kits. These EIA kits are a simple method requiring minimal equipment, for measuring hormone profiles under field conditions. [source] Using the composite variables of reproductive morphology, histology and steroid hormones to determine age and size at sexual maturity for the thorny skate Amblyraja radiata in the western Gulf of MaineJOURNAL OF FISH BIOLOGY, Issue 5 2006J. A. Sulikowski Age at size was linked to sexual maturity in 77 male and 93 female thorny skates Amblyraja radiata from the western Gulf of Maine using three criteria: 1) gross reproductive morphology, 2) histology and 3) steroid hormone concentrations. Age-bias plots and the coefficient of variation from vertebral band counts suggested that the ageing method represented a non-biased and precise approach to the age assessment of A. radiata. Maturity ogives for males, based on data gathered for clasper length, circulating testosterone concentrations and proportion of mature spermatocysts within the testes, predicted that 50% maturity occurred at a total length (LT) of 865 mm and c. 10·90 years of age. For females, maturity ogives, based on data gathered for ovary mass, shell gland mass, follicle size and circulating oestradiol concentrations, predicted that 50% maturity occurred at 875 mm LT and c. 11·00 years of age. Collectively, the results suggest that analysis of several contemporaneous reproductive variables offers an accurate determination of sexual maturity in the thorny skate. [source] Growth, carcass composition and plasma growth hormone levels in cyclically fed rainbow troutJOURNAL OF FISH BIOLOGY, Issue 3 2006R. W. Blake Growth, body composition and plasma growth hormone levels were recorded weekly for 24 weeks in rainbow trout Oncorhynchus mykiss. Underyearling rainbow trout were individually identified using coded tags and placed on either a cyclic feeding regime of 3 weeks of deprivation followed by 3 weeks of feeding or a daily feeding regime. No significant difference was found in standard length and mass among the cyclically fed and daily fed fish at the end of the experiment. For cyclically fed fish, the absolute specific growth rate and condition factor reached a maximum during the last week of refeeding. Cyclically fed fish had a significantly higher moisture and protein content and lower lipid levels relative to fish fed daily. Absolute mass and fat loss in the deprivation phase of the feeding cycle decreased in intensity with subsequent feeding cycles, indicating that the fish were acclimatizing to the feeding regime. It was proposed that this response was an adaptation against possible adverse effects in the adults (e.g. locomotor performance, bone ossification rates, fat deposition rate, growth rate and age at sexual maturity). Plasma growth hormone concentrations were not affected by cyclic feeding indicating that variations in plasma growth hormone concentration are not the cause of compensatory growth in rainbow trout. [source] Regulation of post-larval development in the European eel: thyroid hormone level, progress of pigmentation and changes in behaviourJOURNAL OF FISH BIOLOGY, Issue 1 2003I. M. Jegstrup Based on thyroid hormone concentrations and histological criteria, glass eels of Anguilla anguilla caught in the French Atlantic coast in January and November were found to be late metamorphic. The pigmentation of the glass eels was demonstrated to be regulated by thyroid hormones, and evidence is given that together, the end of the progression of pigmentation, a fully developed gut and a change in behaviour marked the end of metamorphosis. [source] Androgen profiles among Egyptian adults considering liver statusJOURNAL OF GASTROENTEROLOGY AND HEPATOLOGY, Issue 7pt2 2008Cristina E Aguilar Abstract Background and aim:, Hepatitis C virus (HCV) and environmental hepatotoxins may have an indirect influence on health by altering the synthesis and function of hormones, particularly reproductive hormones. We aimed to evaluate liver diseases and sex steroid hormones in Egypt, which has the highest prevalence of HCV worldwide. Methods:, We measured markers of hepatitis B virus (HBV), HCV and schistosomiasis infection as well as liver function in 159 apparently healthy subjects. We measured total testosterone (T), sex-hormone binding globulin (SHBG) and albumin, and calculated the free androgen index. Results:, Anti-HCV antibodies were detected in 51% of men and 42% of women. Based on HCV reverse transcription PCR (RT-PCR) of 44 men and 33 women, 11% of men and 21% of women showed HCV viremia. There was schistosomiasis in 25% of men and 9% of women, and mixed HCV viremia and schistosomiasis in 57% of men and 52% of women. Compared with men with schistosomiasis only (mean 593.3 ± 73.4 ng/dL), T was higher in men with mixed HCV viremia and schistosomiasis (mean 854.5 ± 47.9 ng/dL; P = 0.006) and men with mixed chronic HCV and schistosomiasis (mean 812.1 ± 43.3 ng/dL; P = 0.001). Men with mixed chronic HCV and schistosomiasis had also significantly higher SHBG (mean 57.7 ± 3.9 ng/dL) than males with schistosomiasis only (mean 34.8 ± SE 4.5 ng/dL; P = 0.0003). Conclusion:, Future investigations should consider that a high prevalence of asymptomatic liver disease may alter associations between hormone concentrations and chronic disease etiology. [source] Stress Response of Prolactin-Releasing Peptide Knockout Mice as to Glucocorticoid SecretionJOURNAL OF NEUROENDOCRINOLOGY, Issue 6 2010A. Mochiduki Prolactin-releasing peptide (PrRP) is known to have functions in prolactin secretion, stress responses, cardiovascular regulation and food intake suppression. In addition, PrRP-knockout (KO) male mice show obesity from the age of 22 weeks and increase their food intake. The plasma concentrations of insulin, leptin, cholesterol and triglyceride are also increased in obese PrRP-KO mice. Fatty liver, hypertrophied white adipose tissue, decreased uncoupling protein 1 mRNA expression in brown adipose tissue and glucose intolerance were observed in obese PrRP-KO mice. As we reported previously, PrRP stimulates corticotrophin-releasing factor and regulates the hypothalamic-pituitary-adrenal axis. Therefore, it is speculated that PrRP regulates both food intake and metabolism as a stress responses. In the present study, we compared blood glucose and plasma glucocorticoid concentrations in PrRP-KO mice, and found that PrRP-KO mice showed higher concentrations of blood glucose and corticosterone compared to wild-type mice after restraint stress. By contrast, there were no difference in c-Fos expression in the paraventricular hypothalamic nucleus and plasma adrenocorticotrophic hormone concentrations between the two groups. These results suggest that the different stress responses as to glucocorticoid secretion may be induced by different responses of the adrenal glands between wild-type and PrRP-KO mice. Thus, we conclude that PrRP-KO mice become obese as a result of increased food intake, a change in metabolism, and abnormal stress responses as to glucose concentration and glucocorticoid secretion. [source] Absolute serum hormone levels predict the magnitude of change in anterior knee laxity across the menstrual cycleJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 2 2006Sandra J. Shultz Abstract This study aimed to determine whether absolute sex hormone concentrations predict the magnitude of knee joint laxity changes across the menstrual cycle. Twenty-two females (18,30 years, body mass index ,30), who reported normal menstrual cycles for the previous 6 months were tested daily across one complete menstrual cycle for serum levels of estradiol (E,=,pg/mL), progesterone (P,=,ng/mL), and testosterone (T,=,ng/dL), and knee joint laxity (KLax,=,mm displacement at 134N) measured with a standard knee arthrometer. The change in KLax across the cycle (maximum,minimum), and minimum (early follicular) and peak (postovulatory) hormone concentrations were recorded for each subject. A stepwise linear regression determined if the minimum, peak, or absolute change in hormone concentrations would predict the magnitude of change in KLax across the cycle. KLax changed on average 3.2,±,1.1 mm across the menstrual cycle (range, 1.5,5.3 mm). Minimum levels of E (39.9,±,11.8 pg/mL) and P (0.61,±,0.27 ng/mL), coupled with peak concentrations of E (199.6,±,54.9 pg/mL) and T (22.5,±,10.5 ng/dL) explained 57.6% of the change in KLax across the cycle. Greater absolute changes in KLax were observed in response to peak E and T levels when minimum E concentrations were lower and minimum P concentrations were higher in the early follicular phase. The absolute minimum concentrations of E and P in the early follicular phase appear to be important factors in determining the sensitivity of the knee joint's response to changing hormone levels. © 2005 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res [source] Influence of Isoflurane General Anesthesia or Anesthesia and Surgery on Thyroid Function Tests in DogsJOURNAL OF VETERINARY INTERNAL MEDICINE, Issue 1 2009M.A. Wood Background: Anesthesia and surgery affect thyroid function tests in humans but have not been studied in dogs. Hypothesis: Anesthesia and anesthesia with surgery will affect thyroid function tests in dogs. Animals: Fifteen euthyroid dogs. Methods: Prospective, controlled, interventional study. Dogs were assigned to one of 3 groups: control, general anesthesia, and general anesthesia plus abdominal exploratory surgery. Dogs in the anesthesia and surgery groups were premedicated with acepromazine and morphine, induced with propofol, and maintained on isoflurane. Samples for measurement of serum thyroxine (T4), free T4 (fT4) by equilibrium dialysis, triiodothyronine (T3), reverse T3 (rT3), and thyroid-stimulating hormone concentrations were collected from each dog immediately before premedication, at multiple times during anesthesia, surgery, 4, 8, 12, 24, 36, and 48 hours after anesthesia, once daily for an additional 5 days, and once 14 days after anesthesia. Sampling was performed at identical times in the control group. Results: Serum T4 decreased significantly from baseline in the surgery and anesthesia groups compared with the control group at 0.33 (P= 0.043) and 1 hour (P= 0.018), and 2 (P= 0.031) and 4 hours (P= 0.037), respectively, then increased significantly in the surgery group compared with the control group at 24 hours (P= 0.005). Serum T3 decreased significantly from baseline in the anesthesia group compared with the control group at 1 hour (P= 0.034). Serum rT3 increased significantly from baseline in the surgery group compared with the control and anesthesia groups at 8 (P= 0.026) and 24 hours (P= 0.0001) and anesthesia group at 8, 12, 24, and 36 hours (P= 0.004, P= 0.016, P= 0.004, and P= 0.014, respectively). Serum fT4 increased significantly from baseline in the surgery group compared to the control at 24 hours (P= 0.006) and at day 7 (P= 0.037) and anesthesia group at 48 hours (P= 0.023). Conclusions and Clinical Importance: Surgery and anesthesia have a significant effect on thyroid function tests in dogs. [source] Plasma Thyroid Hormone Concentrations in Dogs Competing in a Long-Distance Sled Dog RaceJOURNAL OF VETERINARY INTERNAL MEDICINE, Issue 4 2003David L. Panciera Plasma thyroxine (T4), 3,5,3,-triiodothyronine (T3), total protein, and albumin concentrations were measured in 15 dogs both before and after completion, and in an additional 16 dogs before and 24 dogs after completion, of a long-distance sled dog race. The plasma T4 concentration (mean ± SD) decreased significantly from 18.2 ± 5.4 nmol/L before to 14.3 ± 3.5 nmol/L after the race in dogs evaluated at both times and decreased significantly from 21.8 ± 10.5 nmol/L before to 15.8 ± 4.9 nmol/L after the race in dogs sampled only before or only after the race. The mean plasma T3 concentrations in dogs measured twice decreased significantly from 1.20 ± 0.48 nmol/L before to 0.74 ± 0.42 nmol/L after the race, as well as in dogs measured either before (1.28 ± 0.36 nmol/L) or after (0.69 ± 0.28 nmol/L) the race, respectively. Plasma total protein and albumin concentrations decreased significantly after completion of the race. No significant change was noted in 4 control dogs that did not compete in the race and were tested during a similar time period. The plasma concentrations of T4 and T3 were lower than the normal reference range established for this laboratory in 23 and 39%, respectively, of Alaskan sled dogs tested before the race. Plasma thyroid hormone concentrations frequently are below normal in conditioned Alaskan sled dogs and are further reduced after prolonged submaximal exercise. [source] Idiopathic Hypercalcemia in CatsJOURNAL OF VETERINARY INTERNAL MEDICINE, Issue 6 2000A.M. Midkiff Unexplained hypercalcemia has been increasingly recognized in cats since 1990. In some instances, hypercalcemia has been associated with calcium oxalate urolithiasis, and some affected cats have been fed acidifying diets. We studied the laboratory findings, clinical course, and treatment of 20 cats with idiopathic hypercalcemia. Eight (40%) of the cats were longhaired and all 14 cats for which adequate dietary history was available had been fed acidifying diets. Clinical signs included vomiting (6 cats), weight loss (4 cats), dysuria (4 cats), anorexia (3 cats), and inappropriate urinations (3 cats). Hypercalcemia was mild to moderate in severity, and serum parathyroid hormone concentrations were normal or low. Serum concentrations of phosphorus, parathyroid hormone-related peptide, 25-hydroxycholecalciferol, and calcitriol were within the reference range in most cats. Diseases commonly associated with hypercalcemia (eg, neoplasia, primary hyperparathyroidism) were not identified despite thorough medical evaluations and long-term clinical follow-up. Azotemia either did not develop (10 cats) or developed after the onset of hypercalcemia (3 cats), suggesting that renal failure was not the cause of hypercalcemia in affected cats. Seven of 20 cats (35%) had urolithiasis, and in 2 cats uroliths were composed of calcium oxalate. Subtotal parathyroidectomy in 2 cats and dietary modification in 11 cats did not result in resolution of hypercalcemia. Treatment with prednisone resulted in complete resolution of hypercalcemia in 4 cats. [source] Pharmacokinetics of total thyroxine in dogs after administration of an oral solution of levothyroxine sodiumJOURNAL OF VETERINARY PHARMACOLOGY & THERAPEUTICS, Issue 2 2008G. LE TRAON Oral l -thyroxine (l -T4) supplementation is used to replace thyroid hormone concentrations in dogs with hypothyroidism. The pharmacokinetics of l -T4 following administration of a solution (Leventa®) was investigated in healthy dogs. l -T4 was absorbed fairly rapidly (tmax 3 h). A mean bioavailability of 22% was calculated following a single oral administration of 40 ,g l -T4/kg body weight. Repeated oral administration at the same dose for 14 consecutive days did not lead to any accumulation of T4 in serum. After intravenous administration of l -T4, a serum half-life of 11.6 h was calculated. Food intake concomitant with l -T4 oral administration delayed l -T4 absorption and decreased its rate and extent by about 45%. The relative bioavailability of l -T4 following administration of a tablet formulation was about 50% of that of the l -T4 solution. The pharmacokinetic properties of liquid l -T4 after oral administration support the use of a dose rate of 20 ,g/kg once daily, as a starting dose for replacement therapy in dogs with hypothyroidism. [source] Blubber testosterone: A potential marker of male reproductive status in short-beaked common dolphinsMARINE MAMMAL SCIENCE, Issue 3 2009Nicholas M. Kellar Abstract A novel molecular technique was used to measure blubber testosterone (BT) in 114 male short-beaked common dolphins, Delphinus delphis, collected from incidental fishery bycatch and strandings. When these concentrations were compared across maturity states, the mean (± SEM) BT levels of mature D. delphis (14.3 ± 3.0 ng/g) were significantly higher than those of pubertal (2.5 ± 0.5 ng/g, P= 0.006) and immature animals (2.2 ± 0.3 ng/g, P < 0.0001). BT concentrations in mature males were significantly higher in summer months (53.9 ± 2.0 ng/g) than during the rest of the year (7.9 ± 0.69 ng/g, P < 0.0001), indicating reproductive seasonality. An analysis of BT in different anatomical locations showed that hormone concentrations were not homogenous throughout the body; the levels in the dorsal fin were significantly lower than in most other areas (F= 5.39, P= 0.043). Conversely, we found no significant differences in BT concentration with respect to subepidermal depth (F= 2.09, P= 0.146). Finally, testosterone levels in biopsies from 138 free-swimming male D. delphis, of unknown maturity state, sampled off California were found to be of concentrations similar to those from the fishery bycatch and stranding samples and revealed an analogous trend with respect to ordinal date. [source] | ||||||||||||||||||||||||||||