Testosterone and 5-a dihydrotestosterone (DHT) are powerful anabolic hormones that stimulate nitrogen retention and protein synthesis (16). During puberty, testosterone acts in concert with other hormones to increase bone mass and to initiate the adolescent growth spurt. In the adult, testosterone is needed to maintain protein anabolism and, thereby, structural proteins. Athletes who use anabolic steroids (i.e., pharmacologically derived testosterone-like compounds) take advantage of this effect to facilitate the development of increased skeletal muscle mass (3,6,16,17,19). This latter action by testosterone results from androgen-receptor binding, which, in turn, increases muscle gene transcription, including that of insulin-like growth factor (IGF)-I (21). In a related fashion, testosterone also decreases myostatin expression (transforming growth factor [TGFJ-P family member and inhibitor of muscle development) (21). Testosterone also stimulates hematopoiesis and increases sodium reabsorption in the kidney. Finally, studies in animals reveal that testosterone also plays a role in increasing skeletal muscle glycogen synthesis and storage (17).
Was this article helpful?