Growth Factors in the Prostate

Abstract

Certain local tissue factors, such as growth factor, in addition to androgens, are involved in the prostate growth. The prostate contains two types of growth factors capable of stimulating DNA synthesis in BALB/3T3 cells. They were divided into low affinity (LoA) type and high affinity (HiA) type by a different affinity for heparin-Sepharose. HiA-type growth factor is further classified into acidic HiA and basic HiA types. Acidic HiA type could be purified from the Dunning tumor (R 3327), a rat prostatic adenocarcinoma, and has a molecular weight of about 19,000 and a pI of about 3.8. Basic HiA type could be isolated from the tissues of human benign prostatic hypertrophy and has a molecular weight of about 12,000 and a pI of about 10.5. They are inactivated by heat and acid treatments. Acidic HiA type appears to be involved in growth of the rat prostate epithelium, and LoA type growth factor is possibly relevant to reproductive physiology because of its coexistence with "probasin," a major secretory protein in the dorsolateral prostate having a strong affinity for spermatozoa.