Biology · Human Reproduction · NEET
Inhibin inhibits only FSH, not LH. This is the single most tested point. The name helps you: Inhibin -> inhibits FSH (both start with the sound of a soft blocking word). LH is controlled by other feedback, mainly steroid hormones. So any NEET option saying inhibin blocks LH, or blocks LH and FSH together, is wrong.
In males, inhibin is secreted by the Sertoli cells inside the seminiferous tubules (the same nurse cells that feed the germ cells). In females, it is secreted by the granulosa cells of the ovarian follicle. Both are the FSH-target cells, so they send inhibin back to switch FSH off. This is classic negative feedback.
Sertoli cells, not Leydig cells. This is a common trap. Leydig (interstitial) cells make androgens like testosterone and respond to LH. Sertoli cells respond to FSH and make inhibin. Remember: FSH -> Sertoli -> inhibin (all part of the FSH loop); LH -> Leydig -> androgens.
Inhibin is a feedback hormone. When sperm production (or follicle growth) is going well, the FSH-target cells release inhibin, which travels to the anterior pituitary and lowers FSH output. This prevents too much FSH and keeps gamete production balanced. It is a fine-tuning brake on the reproductive axis.
They act in opposite directions. GnRH comes from the hypothalamus and stimulates the pituitary to release LH and FSH. Inhibin comes from the gonad and stops the pituitary from releasing FSH. GnRH turns the axis on; inhibin partly turns it off. GnRH acts on the pituitary from above; inhibin acts on it from below (feedback).
No. NEET once framed this as a trap by pairing Relaxin - Inhibin as if they were antagonistic. They are NOT antagonistic because they act on completely unrelated targets: relaxin relaxes pelvic ligaments during childbirth, while inhibin suppresses FSH. Antagonistic pairs work on the same target in opposite ways (like insulin and glucagon on blood glucose).
Identify the correct statement on 'inhibin':
Try the real previous-year questions from this chapter — each with the answer and a full solution.
From the Sertoli cells of the testis in males and the granulosa cells of the ovarian follicle in females. Both are the cells that FSH acts on.
It travels to the anterior pituitary and suppresses the release of FSH. This is negative feedback that keeps gamete production in balance.
No. Inhibin acts only on FSH. LH is controlled mainly by other feedback signals, so any statement linking inhibin to LH is incorrect for NEET.
No. GnRH from the hypothalamus stimulates the pituitary to release LH and FSH, while inhibin from the gonad suppresses FSH. They pull in opposite directions.
NEET repeatedly tests its exact source and target. The 2016 paper directly asked the correct statement on inhibin, and it also appeared as a trap in antagonistic-hormone questions. Knowing 'Sertoli/granulosa -> inhibits FSH' guarantees the mark.
