Abstracts of Submitted Papers

Abstract

The mechanism of alcoholic hyperlipemia was studied in rats fed liquid diets with 36% of calories as ethanol or carbohydrate (controls). ³H was given intragastrically and ¹⁴C-lysine injected intravenously with or without Triton. Ethanol increased serum lipid concentration several fold, mainly in the very low density lipoprotein fraction (VLDL) with enhanced specific activities of both lipid and protein moieties. VLDL labeling was also increased n alcohol fed rats after injecting_Llabeled chylomicrons (¹⁴C-palmitate, ³H-glycerol), and the ¹⁴C/³H ratio tripled, incriminating increased production of serum lipids rather than decreased removal of dietary chylomicrons. Furthermore, blocking serum lipid removal with Triton did not prevent the lipemic effect of ethanol. To investigate the source of increased serum lipids, intestinal lymph was diverteçi Ethanol still increased significantly the incorporation of ¹⁴C-lysine into serum lipoproteins, but not into chylous lipoproteins, indicating a non-intestinal (probably hepatic) site of increased lipoprotein production. However, ethanol also increased lymph lipid output and incorporation of dietary 3H-palmitate into lymph lipids. This may be explained by the findings that ethanol in vitro, or previous ethanol feeding in vivo, inhibited ¹⁴C-palmitate oxidation by intestinal slices. Thus alcoholic hyperlipemia may result from both enhanced hepatic lipoprotein production and decreased intestinal fat oxidation.