A 35-year-old weightlifter who has been injecting testosterone for muscle mass augmentation is evaluated for sterility and found to have an extremely low sperm count. Which of the following is an effect of testosterone and contributes to the mentioned sterility?

Question

Quizplus · Accepted Answer

Exogenous testosterone suppresses the hypothalamic-pituitary-gonadal axis, leading to feedback inhibition of GnRH, which reduces LH and FSH secretion, ultimately decreasing spermatogenesis and causing low sperm count.  Testosterone directly inhibits the secretion of GnRH from the hypothalamus, which affects secretion of LH and FSH and consequently secretion of testosterone. To initiate spermatogenesis, both FSH and testosterone are necessary. To maintain spermatogenesis after puberty, extremely high concentrations of testosterone seem to be required. Systemically administered testosterone does not raise the androgen level in the testes to as great a degree and it additionally inhibits LH secretion. Consequently, the net effect is generally a decrease in sperm count

A 35-Year-Old Weightlifter Who Has Been Injecting Testosterone for Muscle