Androgens
November 1975
in “
Clinics in endocrinology and metabolism
”
TLDR Testosterone is made by Leydig cells, is active when not bound to proteins, and works by binding to receptors in muscles and other tissues.
The document from 1975 discusses the synthesis and biological activity of testosterone, stating that it is primarily, if not exclusively, produced by Leydig cells and released in an episodic manner with slight daily variations. It emphasizes that only the free, non-protein-bound testosterone in the bloodstream is biologically active. This active testosterone enters target cells and binds to specific receptors in the muscle, while in other target tissues, it is converted to 5α-dihydrotestosterone before being taken up by receptors and moved to the nucleus. The document also notes that anti-androgens mainly work by blocking the uptake of these hormones into the cells.
