This lecture explains the hypothalamic-pituitary-testicular (HPT) axis, the neuroendocrine feedback loop that governs male reproductive physiology and spermatogenesis. The hypothalamus secretes gonadotropin-releasing hormone (GnRH) via the hypophyseal portal system to stimulate anterior pituitary gonadotropes, which release luteinizing hormone (LH) and follicle-stimulating hormone (FSH); LH acts on Leydig (interstitial) cells to drive testosterone synthesis, while FSH acts on Sertoli (sustentacular) cells to induce androgen-binding protein secretion, maintain the blood-testes barrier, and support the meiotic and morphological stages of spermatogenesis (mitosis, meiosis I and II, and spermiogenesis). Testosterone and Sertoli-cell-derived inhibin exert negative feedback on the hypothalamus and anterior pituitary, downregulating GnRH, LH, and FSH to maintain homeostatic control of the axis.
This lecture explains the hypothalamic-pituitary-testicular (HPT) axis, the neuroendocrine feedback loop that governs male reproductive physiology and spermatogenesis. The hypothalamus secretes gonad…