Study on the Growth Limiting Mechanism in the Rat Ventral Prostate

Abstract

Summary In search for the mechanism that limits the growth of the prostate, experiments were performed to find evidence for the existence of a prostatic chalone. Inbred rats were hemiprostatectomized to reduce the level of a hypothetical circulating chalone. No evidence of regeneration was found 4 weeks after operation. Other hemiprostatectomized, orchiectomized rats were given androgen to induce prostatic growth. Cell division in the ventral prostate ended when the size of the prostate was only half of that in the control rats. Orchiectomized rats with intrasplenic and intermuscular implants of ventral prostatic tissue from other orchiectomized rats were given androgen. The cell divisions in the prostatic tissue did not end until the total cell number was 170% of that in the control rats. The results indicate that other factors than a prostatic chalone have the dominating role in the mechanism that limits prostatic growth. We wish to express our appreciation to Dr. A. Szolnoky for his precise determination of the prostate DNA content, and to Mr. J. Brachmann for his excellent technical assistance. This work was supported in part by United States Public Health Service Grant No. RR-05648-9 of the National Institutes of Health.