ANABOLIC-ANDROGENIC STEROIDS SIGNALING

Abstract

Androgens exert their effects on various parts of the body, including muscles, bones, hair follicles in the skin, liver and kidney, reproductive, hematic, immune and nervous systems. The effects are modulated by specific cellular "steroid-converting" enzymes, located inside target tissues. All the anabolic steroids currently used are derivates of testosterone or changes of its structure. The most important esterified forms of testosterone include the propionate, cipionate, enhantate and undecanoate ones. The mechanism of action of AAS has not been fully elucidated and it is currently subject of many studies. Several mechanism of action have been proposed to identify the path activated by AAS. Some, like oximetholone, does not bind the androgen receptors: it is assumed that these steroids act after a biological transformation into more active compounds. The 5 alpha-reductase, for example, plays a central role in their mechanism of action; on the other hand, aromatase is responsible for the conversion of AAS in female sex hormones such as estradiol and estrone, which bind to the estrogen receptor, forming estrogen-receptor complex. Steroid hormone receptors (SHRs) are members of the superfamily of nuclear and steroid receptors. In particolar, the functions of the androgen receptors (hAR) involving transciption factors are generally regulated by specific steroid ligands, that is androgens and selective androgen receptor modulators (SARMs).