Response of rat adrenal cholesteryl esters to cold stress

Male rats were maintained on diets containing corn oil or hydrogenated coconut oil. The compositions of the adrenal cholesteryl esters were determined in control animals and in those subjected to cold stress (4 C for 30 min). Total sterol ester content was lower in the stressed rats. In those receiving corn oil there were selective decreases in 16∶1, 18∶2 and 20∶4(n−6) esters but not in 22∶4(n−6). In the coconut oil fed, essential fatty acid (EFA) deficient animals, the decreases in 20∶4(n−6) and 22∶4(n−6) were quite selective, but the concentrations of the cholesteryl esters of 20∶3(n−9) and 22∶3(n−9) were also selectively reduced in the stressed animals. Olive oil and corn oilethyl erucate were employed as dietary fats in a second experiment. Plasma corticosterone was lower in animal fed ethyl erucate and subjected to cold stress. Cholesteryl erucate was the major adrenal ester in animals receiving dietary erucate but it was not well utilized in animals subjected to stress. The cholesteryl esters of linoleate and arachidonate were preferentially utilized in both of these dietary groups. Cholesteryl arachidonate was selectively utilized in all four dietary groups studied and may constitute the preferred substrate for rat adrenal cholesteryl ester hydrolase.