Effects of phytoestrogen-coumestrol on lipid and carbohydrate metabolism in young ovariectomized rats may be independent of its estrogenicity.
Two groups of young ovariectomized female rats received one of two treatments. The first group was fed coumestrol in lab chow (200 microg of coumestrol per day) for 14 days; the second group received coumestrol (40 mg/L) via perfusion medium. There was a significant increase (78% compared with the control group) in the uterine weight after coumestrol treatment, which supports the estrogen-like activity of coumestrol. Phytoestrogen diminished the liver and skeletal muscle glycogen contents by 18% and 29%, respectively, and increased the blood glucose level by 24%. Glycogenolytic activity of coumestrol was observed when it acted directly on the liver areas. Although phytoestrogen did not influence insulin and glucagon blood level, liver and to some degree muscle susceptibility to insulin (measured as hormone binding by insulin receptors) was decreased. Coumestrol increased the content of triglycerides in muscle by 113% and enhanced the liver lipid synthesis from glucose by 179%. Liver cholesterol concentration was increased both after coumestrol feeding (by 12%) and when it acted directly on the liver (by 16%). These observations suggest that coumestrol is in general anabolic with regard to lipid and catabolic within-carbohydrate metabolism of young ovariectomized female rats. Based on the results of this study, it is concluded that influence of coumestrol on lipid and carbohydrate metabolism of ovariectomized rats is in part not related to its estrogenic action.
Nogowski
L
L
Department of Animal Physiology and Biochemistry, University of Agriculture in Poznan, Poznan, Poland.