Effect of a Sequential Oestrogen-Progestin Therapy on the Plasma Level of Oestrogens and Lipids in Post-Menopausal Women

Abstract

With the aim of minimizing side effects of substitution therapy a natural synthetic oestrogen, oestrone sulphate, and norethisterone acetate were administered to 6 oophorectomized women and 4 women with physiological menopause cyclically in order to follow the pattern of physiological variations during the menstrual cycle as closely as possible, without causing bleedings. In addition to assessing the clinical effects and analyses of plasma oestrone and oestradiol-17\g=b\, the metabolic effects on plasma triglycerides, cholesterol and individual phospholipid levels, as well as on the fatty acid composition of lecithin were followed. The oral administration of oestrone sulphate in doses varying with the "cycle" from 0.5 to 1.5 mg/day gave in these women plasma concentrations of oestrone in the lower pre-menopausal physiological range causing cyclic variations in plasma lipids similar to those during a physiological menstrual cycle but did not normalize the plasma oestradiol concentrations and did not give acceptable therapeutic effect. Total phospholipids, total and free cholesterol, triglycerides and the percentage of lecithin were higher, and the percentage of lysolecithin lower in the oestrogen phase, than in the progestin phase. The changes in linoleic acid in lecithin varied inversely with changes in arachidonic acid in lecithin and cyclic variations also occurred in the content of palmitic and stearic acid in lecithin. When previous treatment with ethinyloestradiol was exchanged with oestrone sulphate the total cholesterol values in plasma varied in the opposite direction. The results obtained in this and previous studies suggest different effects of ethinyloestradiol and oestrone (oestrone sulphate?) in the metabolism of certain sterols, and that the effect of oestrone (or oestrone sulphate?) on plasma cholesterol dominates during physiological condition in the follicular phase of the menstrual cycle.