EVIDENCE FOR MECHANISMS OF THE HYPOTRIGLYCERIDEMIC EFFECT OF N-3 POLYUNSATURATED FATTY-ACIDS

Ingestion of modest amounts of n - 3 polyunsaturated fatty acids (PUFA) (2.8% w/w) decreased plasma triglyceride levels in Syrian hamsters by 49%. This was associated with a 45% increase in hepatic carnitine palmitoyl transferase activity. Significantly, at this low level of n - 3 PUFA intake, hepatic peroxisomal oxidation measured as CN- insensitive palmitoyl-CoA dependent NAD reduction was unaffected. Consumption of increasing amounts of dietary n - 3 PUFA up to 2% (w/w) in hamster diets containing 15% fat, gradually decreased plasma triglycerides to 56% of the control levels. The diet induced changes in plasma triglyceride levels were highly correlated (r = -0.97, P < 0.01)-with changes in hepatic carnitine palmitoyl transferase activity. A gradual decrease up to 59% in hepatic phosphatidate phosphohydrolase activity with n - 3 fatty acid consumption was also observed. The hypotriglyceridemic effects of moderate intakes of n - 3 fatty acids are, therefore, associated with changes in key enzymes in hepatic triglyceride synthesis and mitochondrial oxidation, but not peroxisomal oxidation.