Estrogen Induction of Liver Proteins and High-Density Lipoprotein Cholesterol: Comparison between Estradiol Valerate and Ethinyl Estradiol

Abstract

The effects of ethinyl estradiol and estradiol valerate were compared in 135 postmenopausal women during estrogen replacement therapy. Subfractions of high-density lipoprotein (HDL) cholesterol and its apolipoproteins and the serum levels of 2 estrogen-sensitive liver proteins were followed during 3 cycles of unopposed treatment with either ethinyl estradiol 10 or 30 micrograms or estradiol valerate 2 mg daily. Estrogen therapy induced significant and dose-dependent changes in all serum factors except HDL3 cholesterol. The effects of 10 micrograms of ethinyl estradiol upon the lipoproteins were 1.5-2.5 times greater than those of 2 mg of estradiol valerate. Sex-hormone-binding globulin and the pregnancy zone protein were the most sensitive markers for the estrogenic effect and these 2 liver-derived plasma proteins were also much more sensitive to ethinyl estradiol than to estradiol valerate. Although satisfactory therapeutic effects were achieved with both estrogens, the marked influence of ethinyl estradiol on liver protein synthesis should make estradiol valerate the first choice in clinical replacement therapy.