Hypothalamo-pituitary-gonadal axis (HPG axis)

The hypothalamo-pituitary-gonadal axis is an integrated neuroendocrine system comprising the hypothalamus, pituitary gland, and gonads (ovaries or testes). It regulates vital functions including reproductive development, sexual maturation, fertility, and aspects of aging, primarily through complex hormone cascades. Gonadotropin-releasing hormone (GnRH), secreted by the hypothalamus, stimulates the pituitary to release luteinizing hormone (LH) and follicle-stimulating hormone (FSH), which then act on the gonads to regulate production of sex steroids (estrogen, progesterone, testosterone) and gametogenesis. The system features prominent feedback loops, with sex steroids modulating upstream hormone release. Regulatory molecules such as kisspeptin, activin, inhibin, and follistatin also play key roles in axis function and clinical disorders arise when the axis is disrupted[1][2][3][5][6]. This axis is not a molecule, protein, receptor, or gene; instead, it is a biological network. For molecular targeting, refer to specific components such as the GnRH receptor, LH receptor, FSH receptor, or steroid receptors.

Other names

hypothalamic-pituitary-gonadal axishypothalamic-pituitary-ovarian/testicular axisHPG axis