For women with PCOS, hormones like birth control pills can be used to help lessen the effects of this increased level of testosterone. In humans, testosterone plays a key role in the development of male reproductive tissues such as testicles and prostate, as well as promoting secondary sexual characteristics such as increased muscle and bone mass, and the growth of body hair. In its assessment of CV risks and T therapy, the FDA identified a total of only 4 studies suggesting an increased risk, yet none provided solid evidence to support this. Low T levels in men may increase their risk of developing coronary artery disease (CAD), metabolic syndrome, and type 2 diabetes. In particular, retrospective studies hinted at links between low T serum concentrations and increased risks of events such as myocardial infarction and stroke, prompting caution among regulatory bodies and clinicians. Furthermore, the actual exposure to T among the subjects is not clear, as the treatment group was categorized on the basis of a single-filled prescription, and post-treatment T levels were not measured nor was long-term use confirmed. All patients included in this retrospective analysis had low serum T concentrations and had undergone coronary angiography. Vigen et al. reported an association between TRT and the incidence of myocardial infarction, stroke or death in approximately 8000 male veterans . In contrast to the cross-sectional studies mentioned above, these studies have attempted to analyze large populations of men who received exogenous T, presumably as TRT. Nonetheless, the results of the TOM trial provide important cautionary information regarding the potential for TRT to be harmful in at least some populations of older men and points to the need for larger studies. Further, subjects in the TOM trial had higher baseline BMI, higher triglycerides, and lower HDL than individuals included in the second study. There is also development of the prostate gland and seminal vesicles.citation needed Examples include genital virilisation such as midline fusion, phallic urethra, scrotal thinning and rugation, and phallic enlargement; although the role of testosterone is far smaller than that of dihydrotestosterone. The relative potency of these effects can depend on various factors and is a topic of ongoing research. It exerts its action through binding to and activation of the androgen receptor. Testosterone is a steroid hormone from the androstane class containing a ketone and a hydroxyl group at positions three and seventeen respectively. Many authors of systematic reviews on the CV risks of TRT call for a large randomized multicenter trial on this issue. The Rancho Bernardo study also showed an inverse relationship between circulating T levels and plasma VLDL . Most of these studies have also demonstrated an inverse relationship between T levels and both plasma triglycerides 32–34,36 and total cholesterol 32,34. A positive correlation exists between HDL-c and circulating T concentrations, as seen in multiple studies including the San Antonito Heart study , the Tromso study , the Turku Male Aging study , the Rancho Bernardo study , MRFIT and a study from Ghent, Belgium . After adjustment for over 50 variables, those individuals who had received a prescription for T following coronary angiography had a higher incidence of CVD events compared with the group who had not received a T prescription over an average of 27.5 months of follow-up. Importantly, the interpretive value of these randomized controlled trials remains limited, as these studies were not powered to look at CVD events as an outcome. However, this was a small study and there is a need to verify the findings and better understand the functional implications of the observed changes in HDL constituent proteins . This prevents the deposition of cholesterol in the arterial wall and thereby protects against atherogenesis. Focus has shifted from measuring HDL cholesterol content alone to assessing HDL particle function, which may prove a better predictor of CVD risk. For instance, fluctuation in testosterone levels when a child is in distress has been found to be indicative of fathering styles. While the extent of paternal care varies between cultures, higher investment in direct child care has been seen to be correlated with lower average testosterone levels as well as temporary fluctuations. Fatherhood decreases testosterone levels in men, suggesting that the emotions and behaviour tied to paternal care decrease testosterone levels. Physical presence may be required for women who are in relationships for the testosterone–partner interaction, where same-city partnered women have lower testosterone levels than long-distance partnered women. Testosterone levels do not rely on physical presence of a partner; testosterone levels of men engaging in same-city and long-distance relationships are similar. There was a slow but steady decline in average testosterone levels over the study period. The Mayo Clinic scientists who reviewed 30 placebo-controlled trials of testosterone therapy identified only six that reported clinical events. Four small, brief trials of testosterone's effect on treadmill performance in men with heart disease hint that the hormone may be helpful. Testosterone therapy quickly became the standard treatment for men with low levels of the hormone, or hypogonadism, though its role for aging men with normal testicular function remains highly debatable. Hormone therapy produced a modest increase in blood flow to the heart muscle by widening healthy, but not partially blocked, coronary arteries. A similar 2004 study compared testosterone injections with placebo in 10 men with angina and low testosterone levels. Obesity increases the risk of both diabetes and heart disease.
