EFFECTS OF INTRAVENOUS ADMINISTRATION OF ADRENOCORTICOTROPHIN ON THE ADRENAL LIPIDS OF THE RABBIT

Abstract

Groups of male rabbits were killed 10, 20, 30, 60, 120, or 240 min after an intravenous injection of ACTH (4 I.U./kg). Control rabbits were killed before or immediately after adrenocorticotrophin (ACTH) administration. There was a pronounced decrease in the proportion of cholesteryl esters and an increase in the proportion of unesterified fatty acids in the adrenal lipids during the first 30 min after the injection of ACTH. This decrease in the proportion of esterified cholesterol was accompanied by increases in the concentrations of adrenic and docosahexaenoic acids and decreases in the concentrations of linoleic, linolenic and homo-γ-linolenic acids in the cholesteryl esters. From 30 to 240 min after ACTH administration, the concentrations of these polyunsaturated fatty acids in the cholesteryl esters partially reverted to the values in the control rabbits. The fatty acid acid compostions of the adrenal triglycerides, unesterified fatty acids, and phospholipids were unaltered by the administration of ACTH.