Ethanol-induced hyperlipoproteinemia. Crucial role of preceding ethanol intake in the removal of chylomicrons.
Ethanol produces a number of effects in different steps of lipid metabolism which have been suggested to be responsible for the common phenomenon of ethanol-induced hyperlipoproteinemia in man. The occurrence of hyperchylomicronemia has been attributed to an ethanol-specific disturbance of the clearing mechanism of triglyceride-rich lipoproteins. However, the reports on lipolytic activities and the clearance of chylomicrons after ethanol ingestion are contradictory. In this investigation the short-term excess of serum lipoproteins and the lipolytic activities in healthy volunteers were studied after single and prolonged ethanol ingestion followed by an intravenous lipid load. One hour after a single oral dose of ethanol, the intravenous fat tolerance test was unchanged. After an ethanol load over a 5 hr period, the fat tolerance was reduced, although the same ethanol levels at the time of infusion were maintained. In addition, the lipolytic activities of the serum were significantly reduced after 5 hr of ethanol ingestion followed by intravenous fat load. Hence the time relations between ethanol and fat loads determine whether a defect in chylomicron catabolism can be observed or not. A striking difference in the situations when the fat infusions were performed was the development of endogenous hypertriglyceridemia after 5 hr of ethanol ingestion. Since ethanol-dependent differences in the absorption of fat are ruled out by our experimental design, we attribute our findings to a competitive inhibition of chylomicron degradation by VLDL and partial depletion of the lipolytic system by combined endogenous and exogenous hypertriglyceridemia.
D000328:Adult; D002784:Cholesterol / Q000097:blood; D008078:Cholesterol, LDL; D015243:Cholesterol, VLDL; D002914:Chylomicrons / Q000378:metabolism*; D000431:Ethanol / Q000008:administration & dosage / Q000494:pharmacology*; D005217:Fat Emulsions, Intravenous / Q000008:administration & dosage / Q000494:pharmacology; D006801:Humans; D006951:Hyperlipoproteinemias / Q000139:chemically induced*; D007408:Intestinal Absorption; D008077:Lipoproteins, LDL / Q000097:blood; D008079:Lipoproteins, VLDL / Q000097:blood
D008078:Cholesterol, LDL; D015243:Cholesterol, VLDL; D002914:Chylomicrons; D005217:Fat Emulsions, Intravenous; D008077:Lipoproteins, LDL; D008079:Lipoproteins, VLDL; D000431:Ethanol; D002784:Cholesterol