Abstract
High density lipoprotein (HDL) levels are known to be higher in women than in men, and to increase with estrogen use. To assess the effects of estrogens on HDL subspecies, analytic ultracentrifuge measurements of HDL were compared in 11 menopausal estrogen users and 16 controls. The difference in mean schlieren patterns between the groups showed a significantly higher level of HDL with flotation rate (F1.20o)>1.5 (predominantly HDL2) in the users. This was similar to the difference in HDL seen between nonusers of hormones and age‐matched males. A previous study had shown that users of combination oral contraceptives had increased levels of HDL with F1.20o≤3.5 (primarily HDL3) suggesting that the estrogen effect on HDL is altered by the presence of added progestin. The progrestin effect was studied here in more detail in two women with type V hyperlipoproteinemia treated with norethindrone acetate. Reduction in serum triglyceride was accompanied by a reduction in HDL, predominantly in the less dense species (HDL2). Among groups of oral contraceptive and noncontraceptive estrogen and progestin users whose HDL‐cholesterol levels have been reported recently, there was a direct correlation (r=0.86, p<.001) between mean HDL‐cholesterol and triglyceride levels. Endogenous hormonal influences on HDL were assessed by serum hormone and lipoprotein measurements at weekly intervals during two consecutive menstrual cycles in four healthy females. An increase in HDL of highest flotation rate (F1.20o 5–9) was seen, which corresponded with the time of ovulation raising the possibility of pituitary as well as gonadal hormone effects on HDL.