Rol de los andrógenos en la sexualidad del varón

There are few systematic studies of the relationship between blood testosterone concentrations and the symptoms of overt androgen deficiency. Because most testosterone preparations are relatively short-term, the rapid changes in blood testosterone concentrations they cause make it difficult to define any testosterone threshold. By contrast, subdermal testosterone implants provide stable blood testosterone concentrations over days to weeks, while gradually declining to baseline over 5-7 months. Hence, this provides an opportunity to define a blood testosterone threshold for androgen deficiency symptoms by observing androgen-deficient men as their familiar androgen deficiency symptoms return as testosterone pellets slowly dissolve. Among 52 androgen-deficient men who underwent 260 implantations over 5 yr, at the time of return of androgen deficiency symptoms the blood total and free testosterone concentrations were highly reproducible within individuals (F = 0.8, P = 0.49 and F = 1.4, 0.24, respectively) but varied markedly between men (F = 167 and F = 138, both P < 0.001), indicating that each person had a consistent testosterone threshold for androgen deficiency symptoms that differed markedly between individuals. The most reported symptoms of androgen deficiency were lack of energy, lack of motivation, and reduced libido. The symptomatic threshold was significantly lower in men with secondary hypogonadism compared with men with primary or mixed hypogonadism (total, 9.7 +/- 0.5 nmol/liter vs. 11.7 +/- 0.4 nmol/liter and 10.2 +/- 0.3 nmol/liter, P = 0.006; free, 146 +/- 10 pmol/liter vs. 165 +/- 6 pmol/liter and 211 +/- 18 pmol/liter, P = 0.002) but was not affected by the underlying cause of hypogonadism or by specific symptoms of any severity. Despite a wide range in individual thresholds for androgen deficiency symptoms, the mean blood testosterone threshold corresponded to the lower end of the eugonadal reference range for young men. The implications of these observations for the development of more specific quality-of-life measures, as well as for other potential androgen deficiency states such as chronic diseases and aging, remain to be determined.

Secondary hypogonadism is more common than primary gonadal failure and is seen in chronic and acute illnesses. Although testosterone has a role in erections, its importance in erectile dysfunction (ED) has been controversial. Hypogonadism produced by functional suppression of pituitary gonadotropins has been shown to correct with clomiphene citrate, but with a modest effect on sexual function. We wondered if longer treatment would produce improved results. A total of 178 men with secondary hypogonadism and ED received clomiphene citrate for 4 months. Sexual function improved in 75%, with no change in 25%, while significant increases in luteinizing hormone (P<0.001) and free testosterone (P<0.001) occurred in all patients. Multivariable analysis showed that responses decreased significantly with aging (P<0.05). Decreased responses also occurred in men with diabetes, hypertension, coronary artery disease, and multiple medication use. Since these conditions are more prevalent with aging, chronic disease may be a more important determinant of sexual dysfunction. Men with anxiety-related disorders responded better to normalization of testosterone. Assessment of androgen status should be accomplished in all men with ED. For those with lower than normal age-matched levels of testosterone treatment directed at normalizing testosterone with clomiphene citrate is a viable alternative to giving androgen supplements.