Category: endocrine_axis
Reproductive endocrine loop. Hypothalamic GnRH (pulsatile) → anterior pituitary LH + FSH → gonadal steroidogenesis. Males: LH → Leydig cells → testosterone; FSH → Sertoli cells → spermatogenesis support + inhibin B. Females: cycle-dependent — FSH drives follicle growth + granulosa-cell estradiol; LH surge triggers ovulation; corpus luteum produces progesterone. Pharmacology: GnRH AGONISTS (leuprolide, goserelin) produce initial flare then downregulation/desensitization → suppression of LH/FSH — used in prostate cancer, endometriosis, central precocious puberty. GnRH ANTAGONISTS (degarelix, cetrorelix) suppress without flare. Aromatase inhibitors (anastrozole, letrozole) block peripheral estradiol synthesis.