Cholesteryl ester hydrolase activity in adrenal homogenates from normal and essential fatty acid‐deficient female rats

Abstract Cholesteryl ester hydrolase was assayed in adrenal homogenates from mature female rats fed a control (corn oil‐containing) or essential fatty acid (EFA)‐deficient diet. Cholesteryl ester of 16∶0, 18∶0, 18∶1, 18∶2(n−6), 20∶4(n−6) and 22∶4(n−6) were used as substrates. In control rats, the unsaturated esters were hydrolyzed more rapidly than the saturated esters and cholesteryl arachidonate was the preferred substrate of the six investigated; cholesteryl oleate elicited the highest activity in the deficient group. Polyunsaturated esters were hydrolyzed at a significantly lower rate by homogenates from EFA‐deficient rats than by those from control animals. The esters of 18∶1, 18∶2(n−6) and 20∶4(n−6) were hydrolyzed more extenstively in relation to their concentrations in adrenal tissue than were cholesteryl esters of 16∶0, 18∶0 and 22∶4(n−6). This difference was more pronounced in control than in EFA‐deficient rats. No simple relationship of adrenal cholesteryl ester hydrolase activity to ester fatty acid structure or to nutritional essentiality was evident.