L‐norgestrel and progesterone have different influences on plasma lipoproteins

Abstract

Postmenopausal women [26] who had been on cutaneous estradiol treatment for 3-6 mo. were given either 120 .mu.g of l-norgestrel (n = 13) or 300 mg of progesterone (n = 13) sequentially for another 6 mo. The concentrations of cholesterol, phospholipids and triglycerides [TG] were determined in plasma and in the HDL [high density lipoprotein], HDL2, HDL3, LDL [low density lipoprotein] and VLDL [very low density lipoprotein] fractions before and after 1, 3 and 6 cycles of progestin treatment. Already after 11 days on l-norgestrel, the mean HDL cholesterol and the mean HDL phospholipid concentrations were reduced by 15%. The reduction of the HDL-lipids was mainly confined to the HDL2 fraction which was decreased by 25-30%. l-Norgestrel also reduced the mean TG concentration both in the VLDL and the combined LDL + HDL fractions. Progesterone gave only minor changes of the plasma lipids and lipoproteins. Reduced HDL, especially HDL2, concentration, as induced by l-norgestrel, might increase the risk for ischemic heart disease. As regards the effects on the lipoproteins, progesterone might be more suitable than the 19-nortestosterone derivated l-norgestrel for postmenopausal sequential hormonal therapy.