EFFECTS OF DIETARY SATURATED AND POLYUNSATURATED FATS ON ADIPOSE-TISSUE LIPOPROTEIN-LIPASE ACTIVITY

The present study was conducted to compare the effects of dietary saturated and polyunsaturated fats on adipose tissue lipoprotein lipase activity. The adipose tissue triglyceride fatty acid composition and lipid peroxidation fluorescent products accumulation (an index of lipid peroxides production) were also determined. Weanling Sprague-Dawley rats were fed for 4 weeks a purified high-fat diet (60% of energy as lipid) either composed of lard or corn oil. Adipose tissue triglycerides from rats fed the diet rich in polyunsaturated fatty acids (corn oil) had a high proportion (more than 40 %) of linoleic acid compared to rats fed a high-saturated fatty acid (lard) diet (less than 15 %). Epididymal adipose tissue of animals fed the corn oil diet had a higher concentration of lipid peroxidation fluorescent products (P<0.001) but lower enzymatic activity of lipoprotein lipase (P<0.01) than did that of animals fed the lard diet. Lipoprotein lipase activity correlated negatively (r=-0.78, P<0.01) with lipid peroxidation fluorescent products accumulation in the epididymal adipose tissue. When the rats were fed these diets for 13 weeks, epididymal fat pad mass (P<0.02) and body weight (P<0.05) were significantly lower in the rats fed corn oil compared to the lard diet. These results suggest that the relatively lower activity of adipose tissue lipoprotein lipase in corn oil fed rats may relate to high concentration of lipid peroxides in this tissue. © 1990 Pergamon Press plc. All rights reserved.