The effects of dietary lipids on the fatty acid composition of tissue and membrane fractions of spontaneous mammary adenocarcinomas and mammary glands of Strong strain A mice
The fatty acid composition of whole tissue and plasma membrane fractions of mammary adenocarcinomas and normal mammary glands excised from Strong A female mice fed a 15% safflower oil and 15% tallow diets were studied. Previous work has indicated that high fat diets in general and high unsaturated fat diets in particular, influenced tumorigenesis. The mechanism is not clear. Alternig the normal composition and structure of the plasma membrane can result in altered physiological responses.The fatty acid composition of the dietary fat used in this study affected the fatty acid distribution of mammary gland tissue to a greater degree than tumor tissue. Tumor tissue had almost twice the percentage of linoleic acid as normal tissues (17.0% vs. 9.2%). Oleic acid was also elevated in tumor tissue (24.5% vs. 10.9). The normal tissues contained significantly higher proportions of eicosatrienoic acids (13.5%, 12.2%) than did tumorous tissues, regardless of diet (5.8%, 1.1%). It may be that some of these prostaglandin-active fatty acids in tumorous tissues have been diverted into prostaglandin synthesis.Results of this study indicate that the effect of dietary fat on plasma membranes of tumor cells and normal mammary gland cells was minimal. The saturated or unsaturated state of the fatty acids in the diet appear to play a role in the genesis of tumors by changing the availability of linoleic acid and other prostaglandinactive fatty acids.