Effects of dietary fatty acids on linoleoyl coenzyme A desaturase and fatty acid synthetase activities in liver tissue of strain A/ST mice
Dietary linoleate enhances the development of mammary tumors while dietary stearate has a retarding effect. Since linoleate is a precursor of prostaglandin E2 and elevated levels of prostaglandin E2 have been shown to be associated with tumor development, levels of dietary linoleate directly influence the levels of prostaglandin E2 available for tumor development. The development of new tumor tissue also involves a high demand for fatty acids to be incorporated into cell membranes and this demand is for specific types of fatty acids to maintain the required membrane fluidity.Several enzymes play key roles in the synthesis and desaturation of the fatty acids which are converted to prostaglandins and are synthesized for membrane incorporation. Among these are fatty acid synthetase and linoloeyl coenzyme A desaturase. This study examined the activity of these two enzymes in liver tissue of mice maintained on test diets containing varying proportions of the fatty acids stearate and linoleate.Animals fed a high fat (15% of total) diet containing 13.1% stearate were found to have higher linoloeyl coenzyme A deeaturaae activity than animals fed a low fat diet or a high fat diet containing 11.3% linoleate diets. Animals fed the high fat, high stearate diet were found to have a higher fatty acid synthetase activity than animals fed either a low fat diet or the high fat, high linoleate diet.