Inhibin B is produced by ovarian granulosa cells and Sertoli cells. Its primary physiological role in the male is to:

• A Stimulate testosterone production from Leydig cells
• B Negatively feed back on the pituitary to selectively suppress FSH secretion ✓
• C Promote spermatogonial mitosis directly in the seminiferous tubule
• D Inhibit LH secretion to reduce Leydig cell testosterone

Explanation

Inhibin B (dimeric glycoprotein) is secreted by Sertoli cells in proportion to spermatogenic activity. It selectively suppresses pituitary FSH secretion by inhibiting FSH-beta subunit transcription via activin receptor ALK4/5 signalling, without significantly affecting LH. This provides a precise negative feedback loop: as spermatogenesis and Sertoli cell function decline, inhibin B falls, allowing FSH to rise and stimulate recovery. In clinical practice, low inhibin B with elevated FSH indicates spermatogenic failure (non-obstructive azoospermia).

Reference: Guyton & Hall, Textbook of Medical Physiology, 14th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.