Modulation of rat prostatic inhibinlike peptide (PIP) by steroids and protein hormones

Prostatic inhibinlike peptide (PIP) was detected in the ventral but not in the dorsal lobe of rat prostate. On orchiectomy, PIP concentration in the ventral prostate increased significantly, whereas it decreased on testosterone administration and attained value comparable with that in intact control. Estradiol-17 beta treated animals exhibited high levels of PIP in absence of significant alterations in the protein content. The effect of prolactin and human chorionic gonadotropin on PIP concentration was not so prominent at the dose levels studied. The present study thus demonstrates negative regulation of PIP by testosterone and stimulatory effect of estradiol-17 beta on PIP in rat ventral prostrate.