This is a proposal to elucidate the role of 5HBG and its plasma membrane receptor in androgen (A) and estrogen (E) regulation of the human prostate. Aim 1 is to clone and characterize the cDNA encoding the SHBG-R. The receptor will be cloned from human prostate expression libraries. Aim two will determine the effects of SHBG-R on prostatic growth. An immortalized human prostate stromal cell line will be prepared for these studies. The effects of purified SHBG and sex steroids on stromal cell growth in vitro will be determined together with the relationship between the 5HBG-R and cAMP response element-dependent gene regulation.