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Plasma Testosterone Levels (plasma + testosterone_level)
Selected AbstractsTesticular activity is restored by melatonin replacement after suprachiasmatic nucleus lesion or superior cervical ganglionectomy in minkJOURNAL OF PINEAL RESEARCH, Issue 1 2002Daniel L Maurel Subcutaneous melatonin implants were inserted in mink subjected to natural (autumn) or experimental gonadostimulatory short-days (4L:20D), after lesion of the suprachiasmatic nucleus (SCNx) or after superior cervical ganglionectomy (SCGx). Gonad stimulation was assessed by measuring testicular volume and plasma testosterone level. In SCNx and SCGx animals, all measurements were indicative of sexual quiescence. In contrast, both SCNx and SCGx animals with melatonin, maintained in natural or experimental gonadostimulating short-days, showed an increase in testicular activity 2 months after melatonin implantation. Thus, melatonin (and pineal activity) is a prerequisite for the photoperiodic stimulation of reproductive activity, and the SCN is not necessarily the target site for melatonin action on the renewal of reproduction in the mink. [source] Endocrine responses of Fundulus heteroclitus to effluent from a bleached-kraft pulp mill before and after installation of reverse osmosis treatment of a waste streamENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 11 2000Monique G. Dubé Abstract Implementation of process changes on the nonbleaching side of bleached kraft pulp mill (BKPM) operations has increased in recent years to maximize resource use and to minimize residual environmental effects of discharged effluents. The objective of this study was to determine if reverse osmosis (RO) treatment of evaporator and digester clean condensates reduced or removed the effects of a BKPM effluent on reproductive endocrine function of the estuarine killifish, Fundulus heteroclitus (mummichog). Comparison of data collected before (1997) and after (1998), the years of the process change, showed that the potential of the combined mill effluent to depress plasma testosterone levels after 30 and 57 d of exposure to an environmentally relevant effluent concentration (1%) was reduced after RO treatment of condensates. However, in vitro production of some sex steroids was depressed with a 1% effluent exposure after the process change. In addition, in 1998, depression of plasma testosterone levels in effluent-exposed fish was present at higher effluent concentrations (5%). These results are significant because they suggest that condensates may be a source of endocrine-disrupting compounds in BKPM effluents and RO may reduce their discharge. [source] The aging male , diagnosis and therapy of late-onset hypogonadismJOURNAL DER DEUTSCHEN DERMATOLOGISCHEN GESELLSCHAFT, Issue 4 2008Gerhard Schreiber Summary Managing the clinical features of hormone insufficiency in aging men is an important field of activity for dermatologists and in particular for dermatologists specialized in andrology. Potential consequences of age-associated decrease in plasma testosterone levels include long-term changes in diverse organ systems including changes of bone architecture, body composition, muscular strength, cognitive functions, and mood as well as negative effects on skin and hair. Indications and contraindications for a hormone replacement therapy as well as therapy monitoring are well-defined. Replacement of testosterone in the case of late-onset hypogonadism is not a standardized therapy. Previous studies suggest that testosterone replacement therapy has positive clinical effects. Dermatologic effects of testosterone replacement therapy have not yet been investigated. Further research is required to identify potential benefits and risks of hormone replacement therapy in aging men. [source] Effect of Cd transferred via food product on spermatogenesis in the ratANDROLOGIA, Issue 1 2010L. Hachfi Summary The aim of this work was to assess the effect of organic Cd on the pituitary-testicular axis in rats given diet containing Cd incorporated in radish bulb. A control group was assigned a diet containing ordinary radish for 12 week and second received for the same period a diet containing Cd-contaminated radish at the rate of 20 + 2 ,g g,1 of dry weight. At the end of treatments, the rats were anaesthetized, blood samples were collected and epididymides were removed for establishing sperm count. Circulating FSH, LH and testosterone levels were determined by electrochemiluminescence using automate (Elecsys 2110; Rochediagnostics). A decrease in FSH levels was observed in Cd-exposed animals. This seems to be at the origin of the large drop in the number of spermatozoa. Concerning the plasma testosterone levels we observed a significant increase in contaminated animals. Surprisingly, LH does not exhibit any variation, leading to the conclusion that the feedback control between testosterone and LH was disrupted by the use of Cd. In conclusion, our data indicate that the hypothalamic-pituitary axis is the principal target of Cd toxicity. [source] Concurrent improvement of the metabolic syndrome and lower urinary tract symptoms upon normalisation of plasma testosterone levels in hypogonadal elderly menANDROLOGIA, Issue 1 2009A. Haider Summary Central obesity in adulthood, the metabolic syndrome, erectile failure and lower urinary tract symptoms (LUTS) are all associated with lower-than-normal testosterone levels, although the relationship between testosterone and LUTS appears weak. The metabolic syndrome is associated with an overactivity of the autonomic nervous system. Alternatively, the metabolic syndrome is associated with markers of inflammation, such as C-reactive protein (CRP), maybe signalling intraprostatic inflammation. A large cohort of 95 middle-aged to elderly hypogonadal men (T levels 5.9,12.1 nmol l,1) were treated with parenteral testosterone undecanoate and its effects on the metabolic syndrome {waist circumference, cholesterol, CRP and LUTS [residual bladder volume (RBV), International Prostate Symptoms Score (IPSS), prostate volume, prostate-specific antigen (PSA)]} were evaluated. Along with the improvements of the metabolic syndrome, there was a significant decline of the values of the IPSS, RBV and CRP. There was a (low) level of correlation between the decline of waist circumference and residual volume of urine but not with IPSS and prostate size. Along with the improvement of the metabolic syndrome upon testosterone administration, there was also an improvement of the IPSS and of RBV of urine and CRP. The mechanism remains to be elucidated. [source] Relationship between adult dark spermatogonia and secretory capacity of Leydig cells in cryptorchidismBJU INTERNATIONAL, Issue 5 2007Dragana Zivkovic In a paper from Switzerland, the authors describe the relationship between adult dark spermatogonia and the secretory capacity of Leydig cells in cryptorchidism. OBJECTIVE To examine whether hormonal therapy before orchidopexy affects the histology of the testis and to assess the responsiveness of the Leydig cells, as it has been shown that although basal plasma testosterone levels are within the ,normal' range in cryptorchid boys there is an insufficient increase of testosterone after a human chorionic gonadotrophin (hCG) stimulation in ,,30% of cryptorchid boys. PATIENTS AND METHODS In all, 55 boys (aged 1,7 years) with a unilateral undescended testis were included in the study and divided into two groups. Group I (32 boys) received hormonal therapy before orchidopexy; 17 boys received a long-acting LHRH analogue (buserelin) administered as a nasal spray in doses of 20 µg/day for 28 days, followed by 1500 IU hCG intramuscularly (i.m.) once a week for 3 weeks, and the remaining 15 received 1500 IU hCG i.m. once a week for 3 weeks. Group II (33 boys) had orchidopexy alone. During orchidopexy biopsies were taken from the undescended and contralateral descended testes of the boys in both groups for histological analyses. Variations in the number of adult dark (Ad) spermatogonia per tubule (Ad/T) were assessed and testosterone levels were measured during the course of the hormonal therapy (before treatment, 14 days after initiation of buserelin administration, 24 h after each hCG injection, and 3 months after cessation of therapy). RESULTS In group I, 17 boys (53%) had a ,normal' Ad/T after hormonal treatment vs only six (18%) in group II after orchidopexy alone (P = 0.019). In the hormonally treated boys (group I) we compared the testosterone values 24 h after the second injection of hCG (when the response was most pronounced). Those with a normal Ad/T had a mean (sd) testosterone level of 199.5 (97.6) ng/dL vs 99.6 (85) ng/dL in those with an inadequate Ad/T response to hormonal therapy (P < 0.003). CONCLUSION We have confirmed that there are two subgroups of cryptorchid boys. Patients with a sufficient Leydig cell secretory capacity will have normal testicular histology and Ad spermatogonia count after hormonal treatment. While those with a suboptimal Leydig cell capacity will have a low Ad spermatogonia count and consequently poor prognosis for future fertility, despite successful surgery. As to whether different types and durations of the hormonal therapy in patients with impaired Leydig cell response could lead to improved testicular histology and consequently improved prognosis for future fertility, remains to be answered. [source] Dexamethasone administration inhibits skeletal muscle expression of the androgen receptor and IGF-1 , implications for steroid-induced myopathyCLINICAL ENDOCRINOLOGY, Issue 1 2010Warrick J. Inder Summary Context, Glucocorticoids are a well-recognized cause of muscle weakness. The early effects of glucocorticoids on skeletal muscle (SkM) androgen and IGF-1 pathways have not been previously investigated in human subjects. Objective, To determine if administration of the potent glucocorticoid dexamethasone down-regulates SkM androgen receptor and the IGF-1 signalling pathway. Methods and subjects, Twenty-four subjects (12 men and 12 women), including 12 with type 2 diabetes and 12 nondiabetics were enrolled. Venous blood sampling and biopsy of vastus lateralis were performed before and after administration of oral dexamethasone 4 mg/day for 4 days. Main outcome measures, Changes in plasma testosterone and IGF-1, SkM androgen receptor mRNA, SkM IGF-1mRNA and SkM IGF-1 receptor mRNA by quantitative RT-PCR after dexamethasone. Results, Relative expression of SkM androgen receptor was similar in male (1·63 ± 0·37) vs. female (1·57 ± 0·30) subjects, despite the significant difference in plasma testosterone levels. Plasma IGF-1 and SkM expression of IGF-1 and IGF-1 receptor were also similar between males and females. Following dexamethasone, there was a significant down-regulation of SkM androgen receptor (1·60 ± 0·23 vs. 1·11 ± 0·16, P < 0·05) and IGF-1 (1·72 ± 0·29 vs. 1·06 ± 0·14, P < 0·05) mRNA, but no change in expression of the IGF-1 receptor. Plasma testosterone fell significantly in both sexes (male: 15·0 ± 1·3 vs. 11·3 ± 1·2 nmol/l, P < 0·01, female: 1·8 ± 0·5 vs. 0·5 ± 0·1 nmol/l, P < 0·05). Conclusions, Exogenous steroid excess results in relative androgen deficiency at two levels, reduced circulating testosterone and SkM androgen receptor mRNA, along with reduced SkM IGF-1 mRNA. These defects may contribute to the development of steroid-induced myopathy. [source] | |||||||||||||