The Role of Dehydroepiandrosterone (DHEA) in Skeletal Muscle.

Dehydroepiandrosterone (DHEA) is a precursor of sex steroid hormones and is converted to testosterone and estradiol. Normally, androgens and estrogens produced adrenal cortex, testis, and ovary; however, recent studies revealed androgens and estrogens are synthesized by peripheral tissues such as brain, skin, liver, kidney, bone, etc. We found skeletal muscles are also capable of synthesizing androgens and estrogens from DHEA. Circulating DHEA provides substrates required for conversion into potent androgens and estrogens in peripheral tissues. Sex steroid hormone administration has important roles: one is that the enhancement of protein synthesis and anabolism, resulting in muscle growth and increased muscle strength. The other is improvement of hyperglycemia through the activation of glucose signaling pathway in skeletal muscle as well as acceleration of muscle lipid metabolism that increase peroxisome proliferator-activated receptor alpha (PPARα) and PPAR delta (PPARδ). We introduce the effect of DHEA and sex steroid hormones administration on muscle glucose and lipid metabolisms as well as the effect of sex steroid hormone on the muscle hypertrophy.