Ovulation Rates and Embryo Degeneracy in Female Mice Fed the Phytoestrogen,Coumestrol 1

Abstract

Abstract

Two trials were conducted to determine the effects of dietary coumestrol upon ovulation rates and embryo degeneracy in mice. When female mice, strain B6 D2 F1, were fed 150, 300, or 900 ppb (parts per billion) coumestrol, ovulation rates were reduced 50, 59, and 66%, respectively. In contrast, the incidence of degenerate embryos increased from 4% for controls to 26, 49, and 81%, respectively. When female mice, strain ICR, were fed 50, 100, 200, or 400 ppb coumestrol, ovulation rates were reduced 30, 36, 42, and 54%, respectively, compared to controls. The incidence of degenerate embryos increased from 3 to 46% with 400 ppb dietary coumestrol. Fertilization rate was not affected by dietary coumestrol in the first trial, but was reduced in the second trial. Uterine weights were increased with all levels of added coumestrol in both trials. Maternal weights were not affected by 900 ppb coumestrol in the first trial, but were significantly reduced by 400 ppb coumestrol in the second trial. Differences may exist among strains of mice in body weight response to dietary coumestrol. Dietary coumestrol markedly reduced ovulation rates and increased embryo degeneracy in female mice treated with PMSG and HCG and fed 50 ppb coumestrol or greater.