Inhibin A

Function

Inhibin A is a glycoprotein hormone involved in reproductive endocrine regulation, follicular development, gonadal signaling, and feedback control of pituitary follicle-stimulating hormone secretion. The hormone functions primarily within the reproductive axis where it helps coordinate communication between gonadal tissues and the pituitary gland.

In females, inhibin A participates in regulation of ovarian follicle maturation, ovulation-associated signaling, and luteal-phase endocrine communication. In males, related inhibin pathways contribute to testicular signaling and reproductive regulation. Through negative feedback mechanisms, inhibin A helps maintain balanced reproductive hormone output and coordinated gonadal function.

Production

Inhibin A is produced mainly by ovarian granulosa cells in females and Sertoli cells in males. In women, production rises during later stages of follicular maturation and during the luteal phase following ovulation. The hormone consists of alpha and beta-A subunits linked to form the biologically active dimeric structure.

Synthesis occurs within gonadal tissues under influence of gonadotropin signaling and reproductive-cycle physiology. Local ovarian production allows both endocrine feedback and paracrine communication within follicular environments.

Regulation

Inhibin A production is regulated by follicle-stimulating hormone, luteinizing hormone, ovarian follicle maturation, reproductive-cycle timing, and gonadal steroid signaling. Follicular development strongly influences secretion dynamics across the menstrual cycle.

Inhibin A acts primarily at the pituitary gland where it suppresses follicle-stimulating hormone synthesis and secretion. Signaling involves interactions with activin-related pathways and transforming growth factor-beta family receptor systems. Feedback regulation between gonads, pituitary gland, and hypothalamic reproductive pathways maintains endocrine reproductive balance. Through these integrated reproductive signaling systems, inhibin A coordinates follicular communication, gonadal feedback regulation, and reproductive endocrine adaptation.