Physiologic 24-Hour Periodicity and Hepatic Phospholipid Metabolism in Relation to the Mouse Adrenal Cortex

¹ From the Division of Cancer Biology of the Department of Physiology and the Departments of Radiology and Physiological Chemistry, University of Minnesota Medical School, Minneapolis, Minnesota

Several groups of male CBC mice 6 weeks of age were studied. Some of the mice were subjected to a sham operation, others to adrenalectomy. The specific activity of phospholipid phosphorus was determined in liver cytoplasm from these mice, killed at two times of day, in each case 2 hours following an injection of radiophosphorus. Significant day-night differences in relative specific activity were found for sham-operated mice. Adrenalectomy was associated with inhibition of day-night differences and lowering of relative specific activity. This lowered relative specific activity of phospholipid phosphorus from liver cytoplasm of adrenalectomized mice was raised back to values within the physiologic range by the administration of 11,17-oxycorticosteroids.