Effects of an Oral Contraceptive Agent on Plasma Lipids, Plasma Lipoproteins, the Intravenous Fat Tolerance and the Post‐heparin Lipoprotein Lipase Activity

Abstract. The plasma lipid and lipoprotein concentration, the intravenous fat tolerance and the post‐heparin lipolytic activity have been studied in 12 healthy young women before and after two months' treatment with a combined oral contraceptive agent. The fasting level of triglycerides increased about 200% and the plasma cholesterol increased 10–20%. The very low density lipoprotein fraction showed a proportionate increase of triglycerides, cholesterol and phospolipids. The amounts of triglycerides of the low and high density lipoprotein families increased both absolutely and relatively and the per cent amount of cholesterol was decreased. The fasting level of free fatty acids was unchanged and the post‐heparin lipolytic activity decreased. The intravenous fat tolerance was unaffected by the treatment. It was suggested that this indicated that the hypertriglyceridemia was due to increased turnover of plasma triglycerides presumedly caused by a raised hepatic secretion. The combined treatment was immediately followed by a period when only the gestagenic component of the drug was given. During this medication the triglyceride and cholesterol levels decreased but remained elevated for at least four and six weeks respectively. This suggests that it was mostly the estro‐genic part of the combined drug that was responsible for the alterations of the lipid levels and that such changes do not disappear immediately after cessation of the estrogen administration.