4 - The Role of Receptors in the Anabolic Action of Androgens

Abstract

The growth-promoting effect of testosterone and its 5 α -metabolites on the male reproductive tract is generally referred to as the androgenic action of this class of steroids. By contrast, the stimulatory effect of these hormones on body weight and nitrogen balance is termed their anabolic action. The major extragenital site of androgen action is on skeletal muscle. However, the magnitude of this response varies widely among individual muscles and between species. The kidney receptor is heat labile and can promote the association of testosterone with purified DNA. These properties of the androgen receptor in mouse kidney are remarkably similar to those of male accessory sexual tissue. This chapter presents studies that suggest that androgens elicit their initial action in mouse kidney nuclei by preferentially stimulating the fractional activity of RNA polymerase II. The ability of progestins to mimic the action of androgens is well recognized. However, demonstration of progestational androgenicity is highly dependent upon the steroid and the end point used.