Testosterone

Testosterone is the principal endogenous male sex steroid hormone belonging to the class of androstane steroids. It has key roles in development and maintenance of male reproductive tissues and secondary sexual characteristics but also affects muscle mass/bone density/mood/libido across sexes. In medicine it serves both diagnostic purposes ("testosterone level")—as an indicator for various diseases—and therapeutic ones when administered exogenously for hypogonadism or other indications. "Testosterone...is used to treat male hypogonadism...and antagonizes the androgen receptor to induce gene expression that causes growth/development..." "It has a role as an androgen...androgenic/anabolic agent." Note on Query Correction: The term "testosterone levels" does not refer directly to any molecular target, but rather describes the measured amount/concentration of the steroid hormone. The correct canonical form would be "testosterone".

Other names

TestosteronTestosteronaAndrost-4-en-17β-ol-3-one17β-hydroxyandrost-4-en-3-oneVirosteroneD4-Androsten-17b-ol-3-one

For drugs targeting testosterone/testosterone signaling: 1. Testosterone replacement therapy increases circulating hormone to restore physiological effects via activation of androgen receptors. 2. Anti-androgens block androgen receptors or inhibit synthesis/metabolism. 3. Aromatase inhibitors reduce conversion to estradiol.