Mitogenic Factors in Prostatic Tissue and Expressed Prostatic Secretion

Abstract

Expressed prostatic secretions and extracts of benign prostatic hyperplasia tissue contain a polypeptide growth factor(s) that stimulates the uptake of [3H]-labeled thymidine by cultured 3T3 fibroblasts. Mitogenic activity was present in expressed prostatic secretions and extracts of benign prostatic hyperplasia tissue. The apparent MW of the mitogenic fractions were estimated to be 300,000, 150,000 and 60,000 daltons for prostatic tissue extracts, and 30,000 daltons for expressed prostatic secretions. Bioassays yielded a mean of 27 units of mitogenic activity per mg protein in expressed prostatic secretions obtained from men with normal and enlarged prostate glands. There was no difference in bioassayable mitogenic activity in the expressed prostatic secretions from normal and benign prostatic hyperplasia samples but gel filtration studies revealed a high MW component present only in samples form men with prostatic enlargement. A dialyzable low MW inhibitor of fibroblast growth was found in the prostatic tissues and expressed prostatic secretions. The characterization studies and the possible roles of growth factors in the pathogenesis of benign prostatic hyperplasia are discussed.