Epidermal Growth Factor is not the Major Growth-Promoting Agent in Extracts of Prostatic Tissue

Abstract

Extracts of benign prostatic hyperplasia (BPH) contain a factor which is mitogenic for human foreskin fibroblasts in culture. Because of the similarity of BPH extract and epidermal growth factor (EGF) in stimulating quiescent fibroblasts to divide, it was of interest to determine if the prostate-associated growth factor competes for EGF receptor binding. BPH extract competed poorly for 125I-EGF-receptor binding, did not influence the dissociation of cell-bound 125I-EGF and caused only a slight down-regulation of the EGF receptor. EGF and BPH extract evidently do not recognize the same receptor, and the major growth-stimulating activity of BPH extract is not due to EGF.