Fig. 1
From: Age-related testosterone decline: mechanisms and intervention strategies
Hypothalamic-Pituitary–Testicular Axis. The hypothalamus secretes gonadotropin-releasing hormone (GnRH), which stimulates the pituitary gland to release luteinizing hormone (LH). LH binds to receptors on Leydig cells (LCs), leading to the production of cyclic adenosine monophosphate (cAMP) and the initiation of steroidogenesis. cAMP, cyclic adenosine monophosphate; GnRH, gonadotropin-releasing hormone; LCs, Leydig cells; LH, luteinizing hormone; Created in BioRender.com