DIFFERENTIAL-EFFECTS OF ESTROGENIC HORMONES ON CELL-PROLIFERATION IN THE COLONIC CRYPT EPITHELIUM AND IN COLONIC CARCINOMATA OF RATS

Abstract

The effect of oophorectomy and of treatment with ovarian hormones on cell proliferation in these tissues is compared. Colonic tumor cell proliferation was retarded following oophorectomy and this retardation was reversed by the administration of estradiol, but not by the administration of progesterone. Oophorectomy did not retard cell proliferation in the colonic crypts. The possible significance of these findings in relation to age-dependent variations in the sex ratio for human bowel cancer is discussed.