Follicle-Stimulating Hormone (FSH)
A gonadotropin hormone produced by the anterior pituitary that stimulates follicle development in women and sperm production in men. Like LH, FSH release is controlled by GnRH and is suppressed by both GnRH agonist (via downregulation) and GnRH antagonist therapy.
Technical Context
FSH is a heterodimeric glycoprotein that drives ovarian follicle growth and oestrogen production in women, and supports Sertoli cell function and spermatogenesis in men. FSH glycosylation patterns affect its biological activity and half-life. The GnRH pulse frequency-dependent regulation of FSH means that very slow GnRH pulses or continuous GnRH paradoxically preserve some FSH production even while LH is suppressed — this differential can be clinically relevant. In IVF protocols, GnRH antagonists (cetrorelix, ganirelix) are used to prevent the premature LH surge while exogenous FSH is administered to stimulate multiple follicle development (controlled ovarian hyperstimulation).