Effects of different progestogens on lipoproteins during postmenopausal replacement therapy.

To study the effects of different types of progestogens on lipoprotein metabolism, we treated three groups of postmenopausal women (six subjects each) for three weeks with estradiol valerate, 2 mg per day, and continued the treatment with different sequential estradiol-progestogen regimens as follows: Group A received norethindrone acetate, 10 mg per day, from Day 15 to Day 24 of the cycle; Group B, medroxyprogesterone acetate, 10 mg per day; and Group C, norgestrel, 0.5 mg per day. These regimens were followed by two consecutive cycles. Total cholesterol decreased in all groups by 10 to 18 per cent from the base-line values (P < 0.05). High-density-lipoprotein (HDL) cholesterol decreased by 20 per cent from the base-line level during treatment with both the estradiol-norethindrone acetate (P < 0.05) and estradiol-norgestrel (P < 0.01) regimens, whereas estradiol with medroxyprogesterone acetate was not associated with a significant change in HDL cholesterol. Our results suggest that the androgenic progestogens of the 19-nortestosterone series reverse the beneficial effect of postmenopausal estrogen treatment on HDL cholesterol, whereas the hydroxyprogesterone derivative medroxyprogesterone acetate has no such effect.