The regulation of male reproductive function is governed by a complex neuroendocrine system known as the hypothalamic–pituitary–testicular (HPT) axis. This axis integrates hormonal signaling to maintain testosterone production and spermatogenesis.
The hypothalamus secretes gonadotropin-releasing hormone (GnRH) in a pulsatile manner, stimulating the anterior pituitary to release luteinizing hormone (LH) and follicle-stimulating hormone (FSH). LH activates Leydig cells in the testes to synthesize testosterone, while FSH acts on Sertoli cells to facilitate germ cell maturation.
Testosterone exerts negative feedback at both hypothalamic and pituitary levels, ensuring hormonal homeostasis. Disruption of this axis may occur due to obesity, systemic illness, pituitary adenomas, chronic stress, or genetic abnormalities.
Clinical evaluation includes measurement of serum erotic testosterone, LH, FSH, prolactin, and, when indicated, pituitary imaging. A comprehensive understanding of this axis is fundamental in diagnosing hypogonadism and infertility.
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