EFFECT OF PROSTATIC INHIBIN PEPTIDE (PIP) ON PROSTATE-CANCER CELL-GROWTH INVITRO AND INVIVO

Prostatic inhibin peptide (PIP), is a 94 amino acid protein which is s ecreted by the prostate gland in an androgen-independent manner. Previ ously, it has been demonstrated that PIP appears to inhibit follicle-s timulating-hormone (FSH) secretion by the pituitary and prostate gland s. In vitro, the Dunning R3327 rat prostate cancer cell line MAT-LyLu (MLL) cells and the human prostate cancer cell line PC-3, are stimulat ed to grow in response to exogenous FSH and these effects are blocked by PIP. In vivo, PIP inhibits the growth of the highly metastatic MLL prostate cancer cell line. A comparison of hormone levels in control a nd PIP-treated rats demonstrates a significant inhibition of FSH in tr eated animals. It appears that, in vivo, PIP may inhibit prostate canc er growth by inhibiting FSH. PIP may represent a novel hormonal treatm ent for prostate cancer.