The infertility with exogenous testosterone implies suppression of which axis?

The infertility with exogenous testosterone implies suppression of which axis?

• A. Hypothalamic-pituitary-adrenal axis suppression
• B. Hypothalamic-pituitary-gonadal axis suppression
• C. Thyroid axis suppression
• D. Renin-angiotensin-aldosterone axis suppression

Answer: (B)

The main concept is how negative feedback in the hypothalamic-pituitary-gonadal axis works when exogenous testosterone is present. Introducing testosterone from outside raises circulating levels, which signals the hypothalamus to reduce GnRH release and the pituitary to lower LH and FSH. With less LH, the testes produce less endogenous testosterone; with less FSH, the support for Sertoli cells and spermatogenesis declines. The result is impaired spermatogenesis and, consequently, infertility, despite high circulating testosterone levels. Other axes aren’t the primary pathways involved here. The hypothalamic-pituitary-adrenal axis (HPA) governs stress hormones like ACTH and cortisol, not directly suppressed by external testosterone. The thyroid axis and the renin-angiotensin-aldosterone system regulate metabolic rate and fluid balance, respectively, and are not the mechanism by which exogenous testosterone causes infertility.

The main concept is how negative feedback in the hypothalamic-pituitary-gonadal axis works when exogenous testosterone is present. Introducing testosterone from outside raises circulating levels, which signals the hypothalamus to reduce GnRH release and the pituitary to lower LH and FSH. With less LH, the testes produce less endogenous testosterone; with less FSH, the support for Sertoli cells and spermatogenesis declines. The result is impaired spermatogenesis and, consequently, infertility, despite high circulating testosterone levels.

Other axes aren’t the primary pathways involved here. The hypothalamic-pituitary-adrenal axis (HPA) governs stress hormones like ACTH and cortisol, not directly suppressed by external testosterone. The thyroid axis and the renin-angiotensin-aldosterone system regulate metabolic rate and fluid balance, respectively, and are not the mechanism by which exogenous testosterone causes infertility.