Lipid composition of liver plasma membranes isolated from rats fed a high glucose or a high fat diet.

Several plasma membrane associated functions have been shown to differ in rats fed a high lard, carbohydrate free diet (L rats) from those observed in preparations from rats fed a high glucose, fat free diet (G rats). To explore the possibility that differences in the lipid components of the plasma membranes might contribute to these functional changes, groups of rats were fed each diet for 5 days and the lipids of their plasma membranes were separated and analyzed. The major differences found were a greater cholesterol content in the plasma membranes from L rats compared to those of G rats (12.2 +/- 2.20 versus 7.8 +/- 1.40 mg/100 mg membrane protein) and more than twice as much phosphatidyl serine and phosphadidyl inositol in the plasma membranes of the former group. Of several variations in fatty acid distribution found in the phospholipid and neutral lipid fractions, the most notable quantitatively were an increase in phospholipid oleic acid (18:1) and a decrease in phospholipid stearic acid (18:0) in L rat plasma membranes. Whether these changes are related to altered membrane function is not known.