The effect of dietary fatty acids on cholesterol/phospholipid ratios and fatty acids in plasma membranes of spontaneous mammary tumors from strain A/ST mice
It has been suggested that plasma membranes play a role in tumor production. Changes in plasma membrane lipid composition may change membrane fluidity and disrupt cellular communication. These changes in membrane lipid composition appear to be related to the fatty acid content of the animal's diet. The purpose of this investigation was to compare the effect of dietary linoleic and stearic acids and tumor size on cholesterol/phospholipid ratios and fatty acids in membranes of mammary adenocarcinomas.Plasma membranes of mammary tumors from Strain A/St mice were isolated by centrifugation and the lipids extracted. Phospholipid content was assayed by the method of Bartlett (102); cholesterol and fatty acids by gas liquid chromatography.Plasma membranes of tumors from mice fed the high linoleic diet (SAFF) were found to have the highest cholesterol/phospholipid ratios (Mean=0.396); mice fed high stearic acid diets produced tumors with the lowest ratios (0.280). Membranes of tumors from mice fed SA-4 and Stock diets had intermediate ratios (0.0.341 and 0.0.346, respectively).