Roles of estrogen and SHBG in prostate physiology.

Heretofore, the function of estrogen in the prostate, other than as an antiandrogen, has been unclear. In this review of a growing fund of knowledge about both estrogen and the plasma protein, sex hormone-binding globulin (SHBG), or testosterone-estradiol binding globulin (TeBG), the hypothesis is proposed that estrogen, mediated by SHBG, participates with androgen in setting the pace of prostatic growth and function. It is suggested that the estrogen not only directs stromal proliferation and secretion, but also, through IGF-I, conditions the response of the epithelium to androgen.