Effect of dietary cholesterol on cholesterol synthesis and plasma membrane lipids of mouse mammary adenocarcinomas and mammary gland tissue

Abstract

The purpose of this research was to determine if a high cholesterol diet can affect tie rate of cholesterol synthesis or to cholesterol and fatty acid content of plasma membranes of mouse mammary a.denocarcinoma and normal mouse mammary gland tissue.Cholesterol synthesizing ability was determined by measuring the incorporation of 14C acetate into digitonin-precipitable sterols from both tumors and normal mammary tissue from Strong A Strain female mice fed a standard lab chow diet (control diet; or a 2% cholesterol experimental diet. Plasma membranes were isolated from both tenors and normal tissue by differential centrifugation. Cholesterol was measured spectrophotometrically. Fatty acids were extracted, methylated, and methylesters identified and quantified using gas liquid chromatography.The rate of incorporation of 111C acetate into digitonin-precipitated sterols in normal mammary tissue from mice fed the 2% cholesterol experimental diet was 1.5 times less than controls. Tumor tissue showed no significant difference. The fatty acid composition of tumor and normal mammary tissue plasma membranes from mice fed the 2% cholesterol experimental diet was similar to controls.There were higher percentages of C16:0 and C16.1 in normal plasma membranes of controls than mice fed the experimental diet. Cholesterol content of to or and normal mammary tissue plasma membranes from mice fed the experimental diet was similar to controls.It would appear that dietary cholesterol does have an effect on cholesterol synthesis in normal mammary tissue but not in marina y tumor tissue. Also dietary cholesterol does not have an effect on the fatty acid composition nor the cholesterol content in plasma membranes of mammary tumors or normal mammary tissue.Ball State UniversityMuncie, IN 47306