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Hormonal Responses (hormonal + response)
Selected AbstractsHormonal Response of Female Goats to Active Immunization against a Recombinant Human Inhibin ,-subunit, and establishment of an Enzyme-linked Immunosorbent Assay for Caprine Follicle-stimulating HormoneREPRODUCTION IN DOMESTIC ANIMALS, Issue 2 2001M Hennies The effect of selective immunosuppression of endogenous inhibin in goats on FSH, LH, progesterone and estradiol-17, profiles was studied during the breeding and nonbreeding seasons. Eighteen adult female Boer goats were immunized against the recombinant human inhibin ,-subunit (hINH-,). With the exception of estradiol, which was determined by radio-immunoassay (RIA), all plasma hormone concentrations were determined by ELISA. The ELISA for FSH presented in this paper was established in the authors' laboratory, based on an existing RIA. Mean basal concentrations of FSH were not affected by immunosuppression of endogenous inhibin, nor was there a difference in the amplitude of the pre-ovulatory FSH surge. Immunization against inhibin appears to eliminate the slight secondary rise of FSH occurring 12,20 h after the major surge associated with ovulation. The LH profiles of the immunized goats were characterized by lower basal concentrations both before and after the pre-ovulatory LH surge which itself was reduced by 50% in immunized does. By contrast, concentrations of circulating estradiol were significantly elevated after inhibin-immunization. Progesterone profiles were not affected. Extending immunization into the anoestrous season by a booster injection of hINH-,, implicating oestrus induction with a progestagen and eCG, produced no discernible differences in FSH and LH profiles in comparison with nonimmunized control goats. The findings suggest that in goats, paracrine factors may play a more significant role in controlling follicular activity than a feedback mechanism acting via the pituitary. [source] Are Hormonal Responses to Exercise in Young Men with Down's Syndrome Related to Reduced Endurance Performance?JOURNAL OF NEUROENDOCRINOLOGY, Issue 5 2008V-A. Bricout The aim of the present study was to analyse whether hormonal responses could explain an exercise limitation in Down's syndrome (DS). Fourteen young men with DS (mean age 22.5 ± 0.7 years) and 15 controls (CONT, mean age 22.5 ± 0.3 years) participated in the study. During a treadmill submaximal incremental test, blood samples were collected for determination of hormonal and metabolic variables. Compared to CONT, DS individuals showed lower VO2max (P < 0.05), and lower duration of submaximal incremental exercise (P < 0.001). At rest, DS individuals showed greater catecholamines, insulin and leptin values (P < 0.05), but lower testosteronemia and cortisolemia (P < 0.05), compared to CONT. During submaximal incremental tests, catecholamines and cortisol were not increased, whereas the insulin concentration of DS individuals was significantly higher (P < 0.01) compared to CONT. Glycaemia increased significantly at the end of submaximal incremental test for CONT but not for DS individuals (P < 0.01). Maximal fat oxidation was lower (P < 0.01), whereas non-esterified fatty acids concentrations rose significantly during submaximal exercise in DS individuals. These results indicate an altered hormonal response to exercise in DS individuals. This endocrine profile at rest and during exercise may limit endurance performance in DS individuals. [source] Analysis of Heritability of Hormonal Responses to Alcohol in Twins: Beta-Endorphin as a Potential Biomarker of Genetic Risk for AlcoholismALCOHOLISM, Issue 3 2000J. C. Froehlich Background: Hormonal responses to alcohol have been reported to differ in subjects with and without a family history of alcoholism which suggests that alcohol-induced hormonal changes might be used to identify individuals who are at elevated genetic risk for developing alcoholism. However, before a biological response can be used as a marker of genetic risk for disease, it must first be demonstrated that the response is, in fact, heritable. The present study was designed to determine whether hormonal responses to alcohol are heritable. Methods: The adrenocorticotropic hormone (ACTH), beta-endorphin (,-E), cortisol (CORT), and prolactin (PRL) responses to alcohol were examined in male and female identical (monozygotic or MZ) and fraternal (dizygotic or DZ) twin pairs. Male subjects consumed 0.35g ethanol/kg body weight (BW) and female consumed 0.325 g ethanol/kg BW in each of two alcohol drinking sessions administered 1 hr apar (total dose of 0.7 g/kg BW in males and 0.65 g/kg BW in females). Plasma hormone content was analyzed in samples collected before (resting conditions) and at 15, 60, 75, 120, 180, and 240 min after onset of drinking. Hormonal responses to alcohol were examined with twin analyses using the TWINAN90 program. A separate analysis was performed for each of the four hormones. A subset of subjects from each zygosity was seen on two separate occasions to establish retest reliability. Heritability of hormonal responses to alcohol was estimated using the intraclass correlation approach before and after removing the contribution of covariates that have the potential of influencing the plasma levels of these hormones. Results: Resting plasma levels of all four hormones were within the expected range, and the ,-E, ACTH, and PRL responses to the alcohol challenge evidenced good test-retest reliability. Of the four hormones examined, the only one that showed significant heritability after alcohol drinking was ,-E. Heritability estimates were not altered for any of the four hormones after removal of the variance contributed by covariates, such as gender and age. Conclusions: Taken together with other recent findings, the results suggest that the ,-E response to alcohol may represent a new biomarker that can be used to identify individuals who are at elevated genetic risk for developing alcoholism. [source] Association of Season and Pasture Grazing with Blood Hormone and Metabolite Concentrations in Horses with Presumed Pituitary Pars Intermedia DysfunctionJOURNAL OF VETERINARY INTERNAL MEDICINE, Issue 5 2010N. Frank Background: Pituitary pars intermedia dysfunction (PPID) is a risk factor for pasture-associated laminitis, which follows a seasonal pattern. Hypothesis: Hormonal responses to season differ between PPID and unaffected horses. Animals: Seventeen horses aged 8,30 years (14 horses , 20 years of age). Methods: Longitudinal observational study. Blood was collected monthly from August 2007 until July 2008 after pasture grazing and again after overnight stall confinement. Blood hormone and metabolite concentrations were measured and pasture grass samples were analyzed to determine carbohydrate content. Analysis of variance analysis for repeated measures was performed. Results: Mean ACTH concentrations varied significantly over time (P < .001), with higher concentrations detected in August, September, and October compared with November,April. Pasture × time effects were detected for glucose and insulin concentrations, with peaks observed in September. Horses were retrospectively allocated to PPID (n = 8) and control (n = 9) groups on the basis of plasma ACTH concentrations. Changes in insulin concentrations over time differed in the PPID group when compared with the control group. Insulin concentrations were positively correlated with grass carbohydrate composition. Conclusions and Clinical Importance: PPID did not affect the timing or duration of the seasonal increase in ACTH concentrations, but higher values were detected in affected horses. Insulin concentrations differed between groups, but hyperinsulinemia was rarely detected. Glucose and insulin concentrations peaked in September when horses were grazing on pasture, which could be relevant to the seasonal pattern of laminitis. [source] Greater growth hormone and insulin response in women than in men during repeated bouts of sprint exerciseACTA PHYSIOLOGICA, Issue 2 2009M. Esbjörnsson Abstract Aim:, In a previous study, sprint training has been shown to increase muscle cross-sectional area in women but not in men [Eur J Appl Physiol Occup Physiol 74 (1996) 375]. We hypothesized that sprint exercise induces a different hormonal response in women than in men. Such a difference may contribute to explaining the observed gender difference in training response. Method:, Metabolic and hormonal response to three 30-s sprints with 20-min rest between the sprints was studied in 18 physically active men and women. Results:, Accumulation of blood lactate [interaction term gender (g) × time (t): P = 0.022], and plasma ammonia (g × t: P < 0.001) after sprint exercise was greater in men. Serum insulin increased after sprint exercise more so in women than in men (g × t: P = 0.020), while plasma glucose increased in men, but not in women (g × t: P < 0.001). Serum growth hormone (GH) increased in both women and men reaching similar peak levels, but with different time courses. In women the peak serum GH level was observed after sprint 1, whereas in men the peak was observed after sprint 3 (g × t; P < 0.001). Serum testosterone tended to decrease in men and increase in women (g × t: P = 0.065). Serum cortisol increased approx. 10,15% after sprint exercise, independent of gender (time: P = 0.005). Conclusion:, Women elicited a greater response of serum GH and insulin to sprint exercise. This may contribute to explaining the earlier observed muscle hypertrophy in women in response to sprint training. [source] Alcohol self-administration acutely stimulates the hypothalamic-pituitary-adrenal axis, but alcohol dependence leads to a dampened neuroendocrine stateEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 8 2008Heather N. Richardson Abstract Clinical studies link disruption of the neuroendocrine stress system with alcoholism, but remaining unknown is whether functional differences in the hypothalamic-pituitary-adrenal (HPA) axis precede alcohol abuse and dependence or result from chronic exposure to this drug. Using an operant self-administration animal model of alcohol dependence and serial blood sampling, we show that long-term exposure to alcohol causes significant impairment of HPA function in adult male Wistar rats. Acute alcohol (voluntary self-administration or experimenter-administered) stimulated the release of corticosterone and its upstream regulator, adrenocorticotropic hormone, but chronic exposure sufficient to produce dependence led to a dampened neuroendocrine state. HPA responses to alcohol were most robust in ,low-responding' non-dependent animals (averaging < 0.2 mg/kg/session), intermediate in non-dependent animals (averaging ,0.4 mg/kg/session), and most blunted in dependent animals (averaging ,1.0 mg/kg/session) following several weeks of daily 30-min self-administration sessions, suggesting that neuroendocrine tolerance can be initiated prior to dependence and relates to the amount of alcohol consumed. Decreased expression of corticotropin-releasing factor (CRF) mRNA expression in the paraventricular nucleus of the hypothalamus and reduced sensitivity of the pituitary to CRF may contribute to, but do not completely explain, neuroendocrine tolerance. The present results, combined with previous studies, suggest that multiple adaptations to stress regulatory systems may be brought about by excessive drinking, including a compromised hormonal response and a sensitized brain stress response that together contribute to dependence. [source] Lunar cycles and reproductive activity in reef fishes with particular attention to rabbitfishesFISH AND FISHERIES, Issue 4 2004Akihiro Takemura Abstract Cues from the moon influence synchrony in growth, feeding, migration, behaviour and reproduction of many reef fishes. Compared with comprehensive studies on the annual and daily activities of fish, few physiological studies have paid attention to the importance of lunar cues in reproductive activities. We review mutual and interesting relationships between fish reproduction and environmental changes induced by the moon, with particular emphasis on the reproductive activity of the rabbitfishes (Siganidae). Rabbitfish species exhibit, in nature, a definitive reproductive season, which differs among the tropical areas. During the reproductive season, synchronous spawning of rabbitfish is associated with a particular lunar phase. The lunar phase used by the respective species is similar in different regions on the earth. Histological observations revealed that gonads develop synchronously towards a peak around the spawning lunar phase, after which the gonads return to spent condition. Concomitant with gonadal development, sex steroid hormones were produced under the influence of gonadotropin (GtH). Injections of human chronic gonadotropin (hCG) to the fish that are undergoing active spermatogenesis accelerated testicular maturation. These results suggest that hormonal response in maturing the gonads in rabbitfish is under the regulation of GtH, and that pituitary secretion of GtH according to the lunar cycle accounts for the lunar rhythm in gonadal development. We speculate that the cues from the moon can be recognized by the higher parts of the hypothalamus,pituitary,gonadal axis. Possible relationships between exogenous environmental factors and the lunar-reproductive rhythm are also discussed. [source] Endocrine Function Is Altered in Chronic Migraine Patients with Medication-OveruseHEADACHE, Issue 4 2006Innocenzo Rainero MD Objective.,To evaluate the effects of analgesic overuse on endocrine function in patients with chronic migraine and medication-overuse headache (CM-MOH). Background.,Chronic migraine is frequently associated with an overuse of symptomatic medications. Drugs currently used in acute migraine attacks are associated with several endocrine effects. At present, the endocrine effects of medication overuse in chronic migraine patients are unknown. Methods.,Eighteen patients with CM-MOH, diagnosed according to the ICHD-II criteria, and 18 healthy controls received an intravenous administration of GHRH, hCRH, and TRH. Plasma concentrations of GH, TSH, ACTH, and cortisol were measured for a 90-minute period after administration of the specific releasing hormones. Results.,Hormonal basal concentrations were similar in both groups. GH response to GHRH was significantly reduced in patients with CM-MOH in comparison with controls. TRH induced a reduction of TSH concentrations only at the end of the test. After hCRH administration, ACTH and cortisol concentrations were significantly higher in cases than in controls. A significant correlation between duration of the disease and altered hormonal response was found. Conclusions.,Our study shows that both corticotropic and somatotropic functions are significantly impaired in CM-MOH patients and suggests a role for hormones in the development of chronic migraine. [source] Noradrenaline Involvement in the Negative-Feedback Effects of Ovarian Steroids on Luteinising Hormone SecretionJOURNAL OF NEUROENDOCRINOLOGY, Issue 10 2009C. V. V. Helena Noradrenaline has been shown to modulate the ovarian-steroid feedback on luteinising-hormone (LH) release. However, despite the high amount of evidence accumulated over many years, the role of noradrenaline in LH regulation is still not clearly understood. The present study aimed to further investigate the involvement of noradrenaline in the negative-feedback effect of oestradiol and progesterone on basal LH secretion. In experiment 1, ovariectomised (OVX) rats received a single injection of oil, oestradiol, or progesterone at 09.00,10.00 h and were decapitated 30 or 60 min later. Levels of noradrenaline and its metabolite, 3-methoxy-4-hydroxyphenylglycol (MHPG), were determined in microdissections of the preoptic area (POA) and medial basal hypothalamus-median eminence (MBH-ME) and correlated with LH secretion. Basal LH levels were decreased 30 and 60 min after oestradiol or progesterone injection, and this hormonal response was significantly correlated with a reduction in POA MHPG levels, which reflect noradrenaline release. In addition, noradrenaline levels in the POA were increased, whereas noradrenaline turnover (MHPG/noradrenaline ratio) was decreased 60 min after the injection of both hormones. No effect was found in the MBH-ME. In experiment 2, i.c.v. administration of noradrenaline (60 nmol), performed 15 min before oestradiol or progesterone injection in jugular vein-cannulated OVX rats, completely prevented the ovarian steroid-induced inhibition of LH secretion. The data obtained provide direct evidence that LH secretion in OVX rats is positively regulated by basal noradrenergic activity in the POA, and its reduction appears to play a role in the negative-feedback effect of ovarian steroids on LH secretion in vivo. [source] Are Hormonal Responses to Exercise in Young Men with Down's Syndrome Related to Reduced Endurance Performance?JOURNAL OF NEUROENDOCRINOLOGY, Issue 5 2008V-A. Bricout The aim of the present study was to analyse whether hormonal responses could explain an exercise limitation in Down's syndrome (DS). Fourteen young men with DS (mean age 22.5 ± 0.7 years) and 15 controls (CONT, mean age 22.5 ± 0.3 years) participated in the study. During a treadmill submaximal incremental test, blood samples were collected for determination of hormonal and metabolic variables. Compared to CONT, DS individuals showed lower VO2max (P < 0.05), and lower duration of submaximal incremental exercise (P < 0.001). At rest, DS individuals showed greater catecholamines, insulin and leptin values (P < 0.05), but lower testosteronemia and cortisolemia (P < 0.05), compared to CONT. During submaximal incremental tests, catecholamines and cortisol were not increased, whereas the insulin concentration of DS individuals was significantly higher (P < 0.01) compared to CONT. Glycaemia increased significantly at the end of submaximal incremental test for CONT but not for DS individuals (P < 0.01). Maximal fat oxidation was lower (P < 0.01), whereas non-esterified fatty acids concentrations rose significantly during submaximal exercise in DS individuals. These results indicate an altered hormonal response to exercise in DS individuals. This endocrine profile at rest and during exercise may limit endurance performance in DS individuals. [source] 5-azacitidine restores and amplifies the bicalutamide response on preclinical models of androgen receptor expressing or deficient prostate tumorsTHE PROSTATE, Issue 11 2010Giovanni Luca Gravina Abstract BACKGROUND Epigenetic modifications play a key role in the in prostate cancer (Pca) progression to a hormone refractory state (HRPC) and the current use of agents targeting epigenetic changes has become a topic of intense interest in cancer research. In this regard, 5-Azacitine (5-Aza) represents a promising epigenetic modulator. This study tested the hypothesis that 5-Aza may restore and enhance the responsiveness of HRPC cells to anti-hormonal therapy on Androgen receptor (AR) expressing (22rv1) and AR-deficient (PC3) cells. METHODS The effects were studied in vitro and in vivo models. This sequential treatment induced in vitro cell cycle arrest and apoptosis both in 22rv1 and PC3 tumor cell lines. RESULTS This combined treatment up-regulated the expression of FasL, phospho-FADD, p16INKA, Bax, Bak, and p21WAF1, and inhibited FLIP, Bcl-2, and Bcl-XL expression. The re-activation of hormonal response of AR-negative PC3 cell line was partially due to the AR re-expression mediated by 5-Aza treatment. In contrast, the increase in the response to anti-androgenic therapy in 22rv1 did not correlate with AR expression levels. Furthermore, xenograft studies revealed that the combined treatment of 5-Aza with AR-antagonist Bicalutamide had additive/synergistic effects in repressing tumor growth in vivo and the underlying mechanisms responsible for these effects seem to be in part mediated by induction of apoptosis. CONCLUSIONS So, this study strongly suggests a therapeutic potential of 5-Aza in combination with anti-androgen therapy in patients with in AR expressing and AR-deficient HRPC. Prostate 70: 1166,1178, 2010. © 2010 Wiley-Liss, Inc. [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] Comparing hormonal and symptomatic responses to experimental hypoglycaemia in insulin- and sulphonylurea-treated Type 2 diabetesDIABETIC MEDICINE, Issue 7 2009P. Choudhary Abstract Aims, Patients with diabetes rely on symptoms to identify hypoglycaemia. Previous data suggest patients with Type 2 diabetes develop greater symptomatic and hormonal responses to hypoglycaemia at higher glucose concentrations than non-diabetic controls and these responses are lowered by insulin treatment. It is unclear if this is as a result of insulin therapy itself or improved glucose control. We compared physiological responses to hypoglycaemia in patients with Type 2 diabetes patients treated with sulphonylureas (SUs) or insulin (INS) with non-diabetic controls (CON). Methods, Stepped hyperinsulinaemic hypoglycaemic clamps were performed on 20 subjects with Type 2 diabetes, 10 SU-treated and 10 treated with twice-daily premixed insulin, and 10 age- and weight-matched non-diabetic controls. Diabetic subjects were matched for diabetes duration, glycated haemoglobin (HbA1c) and hypoglycaemia experience. We measured symptoms, counterregulatory hormones and cognitive function at glucose plateaux of 5, 4, 3.5, 3 and 2.5 mmol/l. Results, Symptomatic responses to hypoglycaemia occurred at higher blood glucose concentrations in SU-treated than INS-treated patients [3.5 (0.4) vs. 2.6 (0.5) mmol/l SU vs. INS; P = 0.001] or controls [SU vs. CON 3.5 (0.4) vs. 3.0 (0.6) mmol/l; P = 0.05]. They also had a greater increase in symptom scores at hypoglycaemia [13.6 (11.3) vs. 3.6 (6.1) vs. 5.1 (4.3) SU vs. INS vs. CON; P = 0.017]. There were no significant differences in counterregulatory hormone responses or impairment of cognitive function among groups. Conclusions, Sulphonylurea-treated subjects are more symptomatic of hypoglycaemia at a higher glucose level than insulin-treated subjects. This may protect them from severe hypoglycaemia but hinder attainment of glycaemic goals. [source] CLINICAL AND IMAGING STUDY: Glucocorticoid negative feedback in methadone-maintained former heroin addicts with ongoing cocaine dependence: dose,response to dexamethasone suppressionADDICTION BIOLOGY, Issue 1 2006Bruno Aouizerate ABSTRACT Combined cocaine and illicit opiate use is common. This study aimed to test the hypothesis that cocaine dependence in former heroin-addicted patients maintained on methadone treatment is associated with enhanced glucocorticoid negative feedback. Multiple dose dexamethasone suppression tests, using a conventional 2.0 mg dose, and two lower doses, 0.5 mg and 0.125 mg, were performed in 10 methadone-maintained former heroin addicts with ongoing cocaine dependence (C-MM), 10 stabilized methadone-maintained former heroin addicts with no ongoing drug or alcohol use (MM), and 22 normal volunteers (NV). At 9 hours, there was no difference in plasma adrenocorticotropin hormone (ACTH) and/or cortisol levels among groups on the baseline day, as well as after the two lower doses of dexamethasone. At 17 hours, C-MM and MM had significantly lower plasma ACTH and/or cortisol levels than NV. However, C-MM did not significantly differ from MM in their hormonal levels. When the hormonal responses to dexamethasone are expressed as magnitude of lowering from baseline, there was no significant difference at any dose among groups. Therefore, C-MM exhibited a normal glucocorticoid negative feedback in the morning. Using the standard interpretation of dexamethasone suppression testing based on the examination of the actual hormonal levels rather than the difference from baseline condition, C-MM appear to have glucocorticoid effects similar to MM, yet were both greater than NV in the late afternoon. Thus, further studies are needed to know whether altered glucocorticoid negative feedback is related to chronic cocaine exposure, or is the result of former heroin addiction and/or its long-term treatment with methadone. [source] Dietary amino acids fed in free form and as protein components do not differently affect postprandial plasma insulin, glucagon, growth hormone and corticosterone responses in ratsJOURNAL OF ANIMAL PHYSIOLOGY AND NUTRITION, Issue 7-8 2006J. A. Nolles Summary This study examined, whether the postprandial fate of dietary amino acids from different amino acid sources is regulated by the responses of insulin, glucagon, corticosterone and growth hormone (GH). Male Wistar rats were cannulated in the vena jugularis and assigned to dietary groups. The diets contained 21% casein or the same amino acids in free form. In the free amino acid diets, methionine level was varied between the groups. The feed was supplied in two distinct meals. In previous experiments it was established that oxidative amino acid losses of the free amino acid diets and protein diets were different. After 3 weeks on those diets, it appeared that the differences in postprandial oxidative losses had been diminished. GH was measured every 12 min, from 144 min before the start of the experimental meal over the following 144 min. Insulin and corticosterone were measured six times from the start of the meal until 270 min after the meal. No differences have been observed between the hormonal responses to both meals at day 5 and at day 26. In conclusion, it has been found that the differences in the oxidative losses between protein and free amino acid meals are not mediated by the combined action of the insulin, glucagon, corticosterone and GH. Postprandial catabolism of amino acids is most probably regulated by substrate induction. [source] Anaesthetic requirement and stress hormone responses in patients undergoing lumbar spine surgery: anterior vs. posterior approachACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 8 2009K. Y. YOO Background: The intensity of nociceptive stimuli reflects the severity of tissue injury. The anaesthetic requirement and stress hormonal responses were determined to learn whether they differ according to different surgical approaches (anterior vs. posterior) during the spinal surgery. Methods: Patients undergoing lumbar spine surgery without neurological deficits were divided into two groups: one having posterior (n=13) and the other having anterior fusion (n=13). The end-tidal sevoflurane concentrations (ETSEVO) required to maintain the bispectral index score at 40,50 were determined. Mean arterial pressure (MAP), heart rate (HR), central venous pressure (CVP), serum osmolality and plasma concentrations of catecholamines, cortisol and vasopressin (AVP) were measured. Results: There were no differences in MAP, HR, CVP and serum osmolality between the groups. ETSEVO was higher in the anterior than in the posterior group (P<0.05). The plasma concentrations of norepinephrine and cortisol increased in both groups during the surgery, whereas those of epinephrine remained unchanged. AVP concentrations increased during the surgery in the anterior group, and remained unaltered in the posterior group. The anterior group needed more analgesics (P<0.01) during the first 1 h after the operation. Conclusions: The anterior approach required a deeper level of anaesthesia while undergoing spinal surgery and more use of post-operative analgesics than the posterior approach. It was also associated with a more pronounced AVP release during the surgery. [source] Are Hormonal Responses to Exercise in Young Men with Down's Syndrome Related to Reduced Endurance Performance?JOURNAL OF NEUROENDOCRINOLOGY, Issue 5 2008V-A. Bricout The aim of the present study was to analyse whether hormonal responses could explain an exercise limitation in Down's syndrome (DS). Fourteen young men with DS (mean age 22.5 ± 0.7 years) and 15 controls (CONT, mean age 22.5 ± 0.3 years) participated in the study. During a treadmill submaximal incremental test, blood samples were collected for determination of hormonal and metabolic variables. Compared to CONT, DS individuals showed lower VO2max (P < 0.05), and lower duration of submaximal incremental exercise (P < 0.001). At rest, DS individuals showed greater catecholamines, insulin and leptin values (P < 0.05), but lower testosteronemia and cortisolemia (P < 0.05), compared to CONT. During submaximal incremental tests, catecholamines and cortisol were not increased, whereas the insulin concentration of DS individuals was significantly higher (P < 0.01) compared to CONT. Glycaemia increased significantly at the end of submaximal incremental test for CONT but not for DS individuals (P < 0.01). Maximal fat oxidation was lower (P < 0.01), whereas non-esterified fatty acids concentrations rose significantly during submaximal exercise in DS individuals. These results indicate an altered hormonal response to exercise in DS individuals. This endocrine profile at rest and during exercise may limit endurance performance in DS individuals. [source] Melanotrope Cells of Xenopus laevis Express Multiple Types of High-Voltage-Activated Ca2+ ChannelsJOURNAL OF NEUROENDOCRINOLOGY, Issue 1 2005H.-Y. Zhang Abstract Pituitary melanotrope cells are neuroendocrine signal transducing cells that translate physiological stimuli into adaptive hormonal responses. In this translation process, Ca2+ channels play essential roles. We have characterised which types of Ca2+ current are present in melanotropes of the amphibian Xenopus laevis, using whole-cell, voltage-clamp, patch-clamp experiments and specific blockers of the various current types. Running an activation current,voltage relationship protocol from a holding potential (HP) of ,80 mV/or ,110 mV, shows that Xenopus melanotropes possess only high-voltage activated (HVA) Ca2+ currents. Steady-state inactivation protocols reveal that no inactivation occurs at ,80 mV, whereas 30% of the current is inactivated at ,30 mV. We determined the contribution of individual channel types to the total HVA Ca2+ current, examining the effect of each channel blocker at an HP of ,80 mV and ,30 mV. At ,80 mV, ,-conotoxin GVIA, ,-agatoxin IVA, nifedipine and SNX-482 inhibit Ca2+ currents by 21.8 ± 4.1%, 26.1 ± 3.1%, 24.2 ± 2.4% and 17.9 ± 4.7%, respectively. At ,30 mV, ,-conotoxin GVIA, nifedipine and ,-agatoxin IVA inhibit Ca2+ currents by 33.8 ± 3.0, 24.2 ± 2.6 and 16.0 ± 2.8%, respectively, demonstrating that these blockers substantially inhibit part of the Ca2+ current, independently from the HP. We have previously demonstrated that ,-conotoxin GVIA can block Ca2+ oscillations and steps. We now show that nifedipine and ,-agatoxin IVA do not affect the intracellular Ca2+ dynamics, whereas SNX-482 reduces the Ca2+ step amplitude. We conclude that Xenopus melanotrope cells express all four major types of HVA Ca2+ channel, as well as the resulting currents, but no low-voltage activated channels. The results provide the basis for future studies on the complex regulation of channel-mediated Ca2+ influxes into this neuroendocrine cell type as a function of its role in the animal's adaptation to external challenges. [source] Lateral parabrachial afferent areas and serotonin mechanisms activated by volume expansionJOURNAL OF NEUROSCIENCE RESEARCH, Issue 16 2008Lisandra Oliveira Margatho Abstract Recent evidence has shown that the serotonergic mechanism of the lateral parabrachial nucleus (LPBN) participates in the regulation of renal and hormonal responses to isotonic blood volume expansion (BVE). We investigated the BVE-induced Fos activation along forebrain and hindbrain nuclei and particularly within the serotonergic clusters of the raphé system that directly project to the LPBN. We also examined whether there are changes in the concentration of serotonin (5HT) within the raphé nucleus in response to the same stimulus. With this purpose, we analyzed the cells doubly labeled for Fos and Fluorogold (FG) following BVE (NaCl 0.15 M, 2 ml/100 g b.w., 1 min) 7 days after FG injection into the LPBN. Compared with the control group, blood volume-expanded rats showed a significant greater number of Fos-FG double-labeled cells along the nucleus of the solitary tract, locus coeruleus, hypothalamic paraventricular nucleus, central extended amygdala complex, and dorsal raphé nucleus (DRN) cells. Our study also showed an increase in the number of serotonergic DRN neurons activated in response to isotonic BVE. We also observed decreased levels of 5HT and its metabolite 5-hydroxyindoleacetic acid (measured by high-pressure liquid chromatography) within the raphé nucleus 15 min after BVE. Given our previous evidence on the role of the serotonergic system in the LPBN after BVE, the present morphofunctional findings suggest the existence of a key pathway (DRN-LPBN) that may control BVE response through the modulation of 5HT release. © 2008 Wiley-Liss, Inc. [source] Thriving in the Face of Early AdversityJOURNAL OF SOCIAL ISSUES, Issue 1 2004Daphne Blunt Bugental Integrating theories drawn from biological, social, and developmental perspectives, Bugental's program of research tracked the outcomes experienced by children born with medical or physical disorders. At risk children who experienced harsh parenting manifested a low ability to cope with stress (e.g., they showed cortisol hyper-reactivity and low habituation). In contrast, at risk children who experienced supportive parenting showed adaptive hormonal responses and an exceptional ability to habituate to stress. Children who were not at risk manifested significantly less reactivity to their parenting history. Harsh parenting, in response to at risk children, was found to be moderated by parents' perceived powerlessness. A cognitively-based home visitation program yielded reductions in child maltreatment and the enhancement of health among infants born at medical risk. [source] Stress Hormone Dysregulation at Rest and After Serotonergic Stimulation Among Alcohol-Dependent Men With Extended Abstinence and ControlsALCOHOLISM, Issue 5 2001Robert M. Anthenelli Background: Alcohol dependence has been associated with long-lasting alterations in limbic-hypothalamic-pituitary-adrenal (LHPA) axis and serotonin (5-hydroxytryptamine [5-HT]) function. Other conditions that are associated with alcoholism (cigarette smoking and antisocial personality disorder [ASPD]) have been linked with disturbances in these interrelated systems. We evaluated the stress hormone response to 5-HTergic stimulation in alcohol-dependent men with extended abstinence (average abstinence duration, 4.3 months) and controls to determine the relative contributions of alcoholism, cigarette smoking, and ASPD on baseline and provoked plasma cortisol and adrenocorticotropin hormone (ACTH) concentrations. Methods: One hundred nine alcohol-abstinent men with alcohol dependence (62%), habitual smoking (70%), and ASPD (43%) received d,l-fenfluramine (100 mg po) in a randomized, double-blind, placebo-controlled, crossover trial. The group of recovering alcohol-dependent individuals included abstinent primary alcohol-dependent men and alcohol-dependent men with ASPD, whereas the group of non-alcohol-dependent men comprised healthy controls and non-alcohol-dependent men with ASPD. Plasma cortisol and ACTH levels were obtained at AM baseline and at half-hour intervals after drug administration. Subjective ratings of drug response and physiological measures were also obtained at baseline and every 30 min. Results: Abstinent alcohol-dependent men had significantly lower (approximately 20%) AM baseline plasma cortisol concentrations than non-alcohol-dependent men on both challenge days; however, no differences between the groups were observed with regard to resting AM plasma ACTH levels. After adjusting for these baseline differences, recovering alcohol-dependent men (area under curve = 35.6 ± 37.4 [,g/dl] × min) had a twofold greater cortisol response to fenfluramine than non-alcohol-dependent men (area under curve = 17.5 ± 32.5 [,g/dl] × min) (F= 5.1;df= 1,105;p < 0.03). The elevated cortisol response, which occurred primarily along the descending limb of the response curve, was paralleled by a nonsignificant statistical trend for alcohol-dependent men to also exhibit a greater ACTH response to fenfluramine at the 210-min (p < 0.07) and 240-min (p < 0.09) time points as compared with non-alcohol-dependent men. Cigarette smoking and ASPD did not affect hormonal responses, nor could the groups' subjective ratings and physiological measures be distinguished. Conclusions: Alcohol-dependent men with extended abstinence differed from age- and race-matched non-alcohol-dependent men in resting AM and fenfluramine-induced plasma cortisol levels. This dysfunction in glucocorticoid homeostatic mechanisms was associated with alcoholism and not with smoking or ASPD. We also observed a nonsignificant statistical trend for plasma ACTH levels to be elevated among alcohol-dependent men along the descending limb of the response curve. Alcohol-dependent men seemed to have inherited or acquired damage to 5-HT-regulated LHPA axis function, the precise mechanisms and sites of which remain to be determined. [source] Analysis of Heritability of Hormonal Responses to Alcohol in Twins: Beta-Endorphin as a Potential Biomarker of Genetic Risk for AlcoholismALCOHOLISM, Issue 3 2000J. C. Froehlich Background: Hormonal responses to alcohol have been reported to differ in subjects with and without a family history of alcoholism which suggests that alcohol-induced hormonal changes might be used to identify individuals who are at elevated genetic risk for developing alcoholism. However, before a biological response can be used as a marker of genetic risk for disease, it must first be demonstrated that the response is, in fact, heritable. The present study was designed to determine whether hormonal responses to alcohol are heritable. Methods: The adrenocorticotropic hormone (ACTH), beta-endorphin (,-E), cortisol (CORT), and prolactin (PRL) responses to alcohol were examined in male and female identical (monozygotic or MZ) and fraternal (dizygotic or DZ) twin pairs. Male subjects consumed 0.35g ethanol/kg body weight (BW) and female consumed 0.325 g ethanol/kg BW in each of two alcohol drinking sessions administered 1 hr apar (total dose of 0.7 g/kg BW in males and 0.65 g/kg BW in females). Plasma hormone content was analyzed in samples collected before (resting conditions) and at 15, 60, 75, 120, 180, and 240 min after onset of drinking. Hormonal responses to alcohol were examined with twin analyses using the TWINAN90 program. A separate analysis was performed for each of the four hormones. A subset of subjects from each zygosity was seen on two separate occasions to establish retest reliability. Heritability of hormonal responses to alcohol was estimated using the intraclass correlation approach before and after removing the contribution of covariates that have the potential of influencing the plasma levels of these hormones. Results: Resting plasma levels of all four hormones were within the expected range, and the ,-E, ACTH, and PRL responses to the alcohol challenge evidenced good test-retest reliability. Of the four hormones examined, the only one that showed significant heritability after alcohol drinking was ,-E. Heritability estimates were not altered for any of the four hormones after removal of the variance contributed by covariates, such as gender and age. Conclusions: Taken together with other recent findings, the results suggest that the ,-E response to alcohol may represent a new biomarker that can be used to identify individuals who are at elevated genetic risk for developing alcoholism. [source] Variations in male parenting behavior and physiology in the common marmosetAMERICAN JOURNAL OF HUMAN BIOLOGY, Issue 6 2009Toni E. Ziegler Infant survival and wellbeing is dependent upon good parenting skills. In some species of primates, fathers are necessary to ensure both positive developmental and social outcomes for their offspring. Common marmosets and the related cotton-top tamarin monkeys provide extensive paternal care of multiple offspring and are essential for infant survival. However, we have found significant variation in a father's motivation to respond to infant stimuli. Additionally, marmoset males who are experienced fathers are significantly more motivated to respond to infants and infant stimuli than adult males who have yet to be fathers. Expectant fathers appear to be preparing for their energetic role in infant care by responding with increases in multiple reproductive hormones and showing weight gain during their mate's pregnancy. Male marmosets have been shown to be hormonally responsive to scent signals. Males show increased testosterone shortly after smelling periovulatory scents and lower levels of testosterone following presentation of their own infant's scent. These two inverse testosterone responses combined indicate that paternal males have a flexible system of responding to socially relevant odor cues. Thus males can be ready to mate when their mate is fertile while continuing to be responsive to their infants when these two events occur simultaneously. A male's hormonal and physical responsiveness to parenting may be due to pair bonding between the male and his mate. Examining the variability between males in their behavioral, physical, and hormonal responses to their mate's pregnancy, and infant stimuli provides the means for determining the mechanisms of good parenting in fathers. Am. J. Hum. Biol., 2009. © 2009 Wiley-Liss, Inc. [source] The relationship between socio-sexual behavior and salivary cortisol in bonobos: tests of the tension regulation hypothesisAMERICAN JOURNAL OF PRIMATOLOGY, Issue 3 2009Gottfried Hohmann Abstract Bonobos are known for their pacifistic behavior and their large repertoire of behaviors that are thought to serve conflict resolution. One is an unusual form of ventro-ventral mounting that facilitates genital contacts (GC). Various hypotheses have been proposed to explain its function. In this study we tested predictions of the tension regulation hypothesis using salivary cortisol as a marker for social stress. The results indicate a temporal relationship between GC and cortisol levels. Compared with baseline data and matched samples of unrestricted food access, rates of GC increased when access to food sources was restricted. Cortisol levels were highest when access to food was constrained. However, because the behavioral and hormonal responses occurred when viewing the stimulus at a distance and preceded the physical presence of the stimulus, we conclude that the anticipation of a competitive situation was sufficient to induce social stress. Contrary to our prediction, targets of aggression did not have higher rates of GC nor did they solicit GC more often than others. Furthermore, higher GC rates did not correlate with a more pronounced decrease in cortisol levels. Not all results obtained in this study supported the predictions concerning the regulatory function of GC on social tension and further research is needed to explore this question. However, the results indicate that the anticipation of competition may be sufficient to induce a costly physiological response, and that high levels of resource competition may have lasting effects on physical stress and stress management. Am. J. Primatol. 71:223,232, 2009. © 2008 Wiley-Liss, Inc. [source] Glucocorticoid levels in free ranging resident mantled howlers: a study of coping strategiesAMERICAN JOURNAL OF PRIMATOLOGY, Issue 8 2007Jurgi Cristóbal-azkarate Abstract A growing amount of data shows that a preference for passive-nonaggressive over active-aggressive problem solving is associated with higher levels of glucocorticoids (GC). For mantled howlers, the arrival of an adult male in a new group is a potential source of psychological stress for both resident males and females. Resident mantled howler males take an active stand and aggressively repel the entrance of solitary males, while females take a passive-nonaggressive stand. In order to study whether the relationship between coping strategies and the activation of the hypothalamic-pituitary-adrenal (HPA) axis observed in other species applies to the response of resident mantled howlers to the presence of solitary males, we examine the relationship between different group and subpopulation variables and the GC levels measured in feces collected from 10 groups living in six forest fragments, in Los Tuxtlas, Mexico. The results of our study suggest that the resident mantled howler females' passive response to the presence of solitary males is accompanied by the activation of the HPA axis, whereas resident males' aggressive response is not accompanied by any changes in the HPA axis. In contrast, a previous study suggests that resident male howlers respond by increasing their testosterone levels to the presence of solitary males (Cristobal-Azkarate et al., Hormones and Behavior 2006;49 261,267). These different behavioral and hormonal responses coincide with the active and passive coping styles described for other species. The conditions in which howlers live in our study area may be favoring the interaction between solitary and resident howlers, and inducing chronically high GC levels, which in turn could negatively affect the fitness of these subpopulations. Am. J. Primatol. 69:866,876, 2007. © 2007 Wiley-Liss, Inc. [source] Arabidopsis mitogen-activated protein kinase MPK12 interacts with the MAPK phosphatase IBR5 and regulates auxin signalingTHE PLANT JOURNAL, Issue 6 2009Jin Suk Lee Summary Mitogen-activated protein kinase (MAPK) phosphatases are important negative regulators in the MAPK signaling pathways responsible for many essential processes in plants, including development, stress management and hormonal responses. A mutation in INDOLE-3-BUTYRIC ACID-RESPONSE5 (IBR5), which is predicted to encode a dual-specificity MAPK phosphatase, was previously reported to confer reduced sensitivity to auxin and ABA in Arabidopsis roots. To further characterize IBR5, and to understand how it might help integrate MAPK cascades with hormone signaling, we searched for IBR5-interacting MAPKs. Yeast two-hybrid assays, in vitro binding assays and in vivo protein co-immunoprecipitation studies demonstrated that MPK12 and IBR5 are physically coupled. The C-terminus of MPK12 appears to be essential for its interaction with IBR5, and in vitro dephosphorylation and immunocomplex kinase assays indicated that activated MPK12 is efficiently dephosphorylated and inactivated by IBR5. MPK12 and IBR5 mRNAs are both widely expressed across Arabidopsis tissues, and at the subcellular level each protein is predominantly localized in the nucleus. In transgenic plants with reduced expression of the MPK12 gene, root growth is hypersensitive to exogenous auxins, but shows normal ABA sensitivity. MPK12 suppression in an ibr5 background partially complements the ibr5 auxin-insensitivity phenotype. Our results demonstrate that IBR5 is a bona fide MAPK phosphatase, and suggest that MPK12 is both a physiological substrate of IBR5 and a novel negative regulator of auxin signaling in Arabidopsis. [source] | ||||||||||||||||