High density lipoprotein subfractions during oral and cutaneous administration of 17 beta-estradiol to menopausal women.

Thirty eight women with menopausal vasomotor symptoms were randomly allocated to 6 months treatment with either 2-4 mg micronized estradiol given orally or 3 mg estradiol applied cutaneously. The concentrations of cholesterol (C) and phospholipids (PL) were determined in high density lipoprotein (HDL) and its subfractions HDL2 and HDL3 twice before treatment and after 2, 4, and 6 months of medication. Oral estradiol increased the C and PL concentration in the HDL2 fraction in a dose-dependent way. With 2 mg estradiol orally the HDL3 fraction did not change, whereas 4 mg estradiol orally increased the C and PL concentrations in the HDL3 fraction. Cutaneous treatment with estradiol did not influence the lipid level in HDL or its subfractions. It is concluded that the rise of HDL during estrogen treatment is mainly caused by an elevation of the HDL2 fraction. Furthermore, the route of administration of estrogens has a profound influence on the metabolism of the HDL subfractions.