Cholesteryl ester hydrolase activity in adrenal homogenates from normal and essential fatty acid-deficient female...

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 extensively 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.