| Summary: | 碩士 === 國立成功大學 === 生理學研究所 === 92 === Estrogen replacement therapy has been used to relieve postmenopausal symptoms and may have beneficial effects on cardiovascular disease. However, the fear of potential risks of breast and endometrial cancers is always a major concern. Accumulating evidences have shown that the consumption of dietary soy protein, that is rich in isoflavone phytoestrogens, is associated with a decreased incidence of cardiovascular disease and breast cancer. This study wants to compare the estrogenic actions of 17□-estradiol (E2) and phytoestrogens in apoE-deficient mice. Immature or mature mice were ovariectomized and then fed cholesterol-rich diet mixed with different doses of E2 or phytoestrogen containing products prepared from soy or red clover. After 12 - 16 weeks, mice were sacrificed and sera were collected for the measurements of cholesterol, triglycerides, LDL-cholesterol and HDL-cholesterol. Aortic fat deposition was examined by oil red O staining and the growth of mammary gland was analyzed by whole-mount preparation. The results show that the treatment of E2 for 12 weeks decreased plasma cholesterol levels, and increased ductal length and numbers of branch points of mammary gland. But it did not affect the extent of atherosclerosis. Phytoestrogens from soy or red clover exhibited no significant effects on plasma cholesterol levels and atherosclerosis. Red clover product did not stimulate mammary gland growth, but soy product at high concentration slightly increased ductal length and numbers of branch points in mammary gland. In summary, phytoestrogens from soy and red clover are not as effective as E2 in affecting plasma cholesterol levels and mammary gland growth.
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