Gonadotrophs

Gonadotrophs are specialized endocrine cells in the anterior pituitary gland that secrete the gonadotropins luteinizing hormone (LH) and follicle-stimulating hormone (FSH). In humans they account for about 10–15% of anterior pituitary cells. The two hormones are glycoproteins composed of a common alpha subunit and distinct beta subunits (LHβ and FSHβ); the alpha subunit is shared with other glycoprotein hormones such as TSH and hCG.

Gonadotrophs are regulated primarily by gonadotropin-releasing hormone (GnRH) from the hypothalamus, released in pulsatile fashion. The frequency and amplitude of GnRH pulses influence the relative secretion of LH and FSH: rapid pulses favor LH synthesis and release, whereas slower pulses favor FSH. Steroid feedback from the gonads (estrogens, androgens, progesterone) modulates GnRH neuron activity and pituitary sensitivity, helping to regulate reproductive cycles.

LH and FSH act on the gonads via specific receptors: LH receptors on Leydig cells in the testes stimulate testosterone production and, in the female ovary, support ovulation and corpus luteum formation; FSH receptors on Sertoli cells in the testes support spermatogenesis and on ovarian granulosa cells promote follicular growth and estrogen synthesis. Signaling is mediated via cAMP and downstream gene regulation.

Clinically, impaired GnRH or pituitary function can cause hypogonadotropic hypogonadism with low LH/FSH; gonadotroph adenomas can secrete gonadotropins or compress surrounding tissue; gonadal failure can elevate LH/FSH (hypergonadotropic hypogonadism).