Testosterone Treatment Of Males Research Articles

Does the 2nd and 4th digit ratio reflect prenatal androgen exposure?

The aim of our study was to describe the effect of prenatal testosterone exposure on 2D:4Din both sexes, and todeterminewhetherthis effectismediated via the androgen receptor. In addition, the sex differences in lengths of 2D, 4D, and 2D:4D ratio were analyzed. Clinical studies suggest a negative correlation between prenatal testosterone exposure and ratio of thelengths ofthe second and fourth digits (2D:4D). However,less is known about the underlying molecular mechanisms. Pregnant rats were treated with olive oil, testosterone, flutamide or testosterone with flutamide daily from the fourteenth day of pregnancy until delivery. The finger lengths of adult offspring were measured using both, digital scanning of the paws and μCT analysis of the phalanges. None of the aforementioned methods revealed any effect of testosterone on 2D:4D.μCT measurements showed that prenatal hyperandrogenism in both sexes leads to shorter 2D compared to controls. Moreover, the testosterone treatment in males resulted in the shortening of 4Dwhen compared to controls. Prenatal hyperandrogenism leads to shorter lengths of 2D and 4D;however, itdoes not affect2D:4D ratio. Whether other steroid hormones and/or testosterone metabolites affect the 2D:4D ratio requires further investigation (Tab. 5, Fig. 3, Ref. 32).

Context-dependent effects of testosterone treatment to males on pair maintenance behaviour in zebra finches

Monogamous pair bonds can be transient or long-lasting, which varies across species. The neuroendocrine mechanisms regulating pair maintenance behaviours are largely unknown, yet fundamental to our understanding of monogamy. Furthermore, the expression and regulation of pair maintenance behaviour is likely to be greatly influenced by social and environmental contexts. Our previous research suggested that androgens might regulate long-term pair maintenance behaviour in the monogamous zebra finch, Taeniopygia guttata. Here, we tested the hypothesis that testosterone treatment to males affects long-term pair maintenance behaviour in zebra finches. Established pairs were randomly assigned to one of two groups: control (N = 8) or testosterone (N = 7). Males were given either an empty or a testosterone-filled Silastic implant. Physical and acoustic affiliative behaviours and plasma testosterone levels were examined at three time points: pre-implantation, 30 days post-implant and 60 days post-implant. Importantly, we examined affiliative behaviours under two contexts: in the home cage (baseline) and following a brief chase (post stressor). Male testosterone treatment had no effects on behaviour during the baseline period, but significantly affected behaviours during the post stressor period. Specifically, testosterone-treated males spent less time in close proximity to their partner and sang more. To our knowledge, this is the first report of a context-dependent effect in the neuroendocrine regulation of pair maintenance behaviour, as well as the first report of an inhibitory effect of testosterone on zebra finch pairing behaviours. These results raise interesting questions about the function of affiliative behaviours in established pair bonds.

Effects of testosterone treatment on body composition in males with testosterone deficiency syndrome

Objective: We evaluated the safety of testosterone treatment and its efficacy on body composition in males with testosterone deficiency syndrome (TDS) over 24 months.Methods: 50 males aged 50–65 years with TDS (Aging Males Symptoms Scale [AMS] > 26 and calculated free testosterone [cFT] 250 pmol/l) were administered 50 mg testosterone gel daily for one year. During the second year, patients received 1000 mg of testosterone undecanoate every 2–3 months. Outcome measures were clinical chemistry values and total testosterone; sex hormone-binding globulin and cFT, changes in AMS and International Prostate Symptom Score; and changes in body composition measured by dual-energy-x-ray absorptiometry.Results: There were no clinically significant changes in clinical chemistry safety parameters. There were significant improvements in both total and cFT and in AMS scores after three months (p < 0.001). Lean mass increased 2.35% at 12 months and 4.5% at 24 months, but proportionally more muscle mass was gained in arms and legs than in the trunk. Fat mass decreased 4.2% at 12 months and 9.1% at 24 months.Conclusions: Testosterone treatment in males with TDS leads to body changes affecting lean and fat mass with significant improvement in AMS scores, and has an excellent safety profile.

REGULATORY EFFECTS OF ESTROGEN AND PROGESTERONE ON THE ADIPOSE RESISTIN EXPRESSION

Resistin, a hormone secreted by adipocytes, is suggested to be an important link between obesity and diabetes. In addition, resistin gene expression increases during adipogenesis, and its serum levels are elevated in both genetically or diet-induced obese mice. To elucidate the role of resistin, the endocrine mechanisms that regulate resistin expression will be remarkable. Several studies revealed that resistin expression is regulated by hormone, including glucocorticoids, endothelin-1, etc. Gender difference in resistin expression was also reported, the expression was higher in male than female mice, and was significant enhanced after testosterone treatment in males, but not in females. In addition to resistin, estrogen has been implicated in the regulation of adipocytokines expression and secretion. Progesterone is another sex hormone possessing pivotal physiological functions in estrus cycle. A cluster of studies strongly indicated the regulatory effect of progesterone on estrogen action in various aspects, including neuro-protection, vasodilatation, and carbohydrate metabolism. We hypothesized that the resistin expression is co-regulated by both estrogen and progesterone. The aim of this study was to evaluate the regulatory effect of estrogen and progesterone on adipocyte resistin gene expression in ovariectomized (OVX) rats, isolated rat adipocytes and 3T3-L1 adipocytes in vitro. Our preliminary results show that subcutaneous injection of estradiol benzoate (EB) reduced resistin mRNA levels in adipocytes isolated from the inguinal, parametrial, perirenal, retroperitoneal, or periovarian fat deposits of OVX rats, while an in vitro study showed that estradiol treatment decreased resistin mRNA levels in cultured rat adipocytes. Both in vivo and in vitro studies show that progesterone (P4) has no regulatory effect on resistin mRNA expression in rat adipocytes. In 3T3-L1 adipocytes, both EB and P4 have no effect on resistin mRNA expression. These data suggest that estrogen is a pivotal regulator of resistin gene expression. The underlying mechanism mediate EBregulated resistin expression will be explored in the further studies. (poster)

Effect of testosterone treatment on vasoconstrictor response of left anterior descending coronary artery in male and female pigs.

Androgens may be risk factors in the pathogenesis of coronary artery disease by promoting coronary vasoconstriction. We studied the effect of testosterone treatment on coronary vascular reactivity of male and female domestic pigs treated for 2 weeks with either placebo or testosterone 10 mg/kg subcutaneous (s.c.) pellets. Vascular reactivity was studied in ring segments (4-5 mm) isolated from the left anterior descending coronary artery (LAD). No significant sex difference was noted in the response of LAD segments from placebo-treated male and female animals to KCl and prostaglandin F2 alpha (PGF2 alpha). Androgen treatment increased the maximum response (Tmax) of intact vessels to KCl from 3,647 +/- 689 mg in controls to 8,939 +/- 1,284 mg in testosterone-treated males (p < 0.01) and from 3,405 +/- 669 to 10,524 +/- 1,663 mg in testosterone-treated female pigs (p < 0.01). Testosterone similarly increased the response to PGF2 alpha 10(-6) M from a mean of 2,149 +/- 1,036 to 3,163 +/- 867 mg in males (p < 0.05) and from 2,076 +/- 810 to 3,565 +/- 578 mg in female segments (p < 0.05). Endothelial denudation significantly decreased the potentiating effect of testosterone treatment in males to both KCl and PGF2 alpha (p < 0.05), but not in segments from females. Our data show that testosterone treatment potentiates contractility of porcine LAD segments to both receptor- and nonreceptor-mediated agonists. In male pigs, this effect may be mediated by an effect on endothelium.