Influence of the adrenal glands on DNA synthesis in normal and compensating kidneys

The role of the adrenal glands in controlling the synthesis of deoxyribonucleic acid in normal and compensating kidneys of rats given saline drinking fluid was studied using tritiated‐thymidine and radioautography. Adrenalectomy alone increased significantly the labeling indices of the renal cortex and medulla of otherwise intact rats. Two days following unilatral nephrectomy of rats with intact adrenal glands, the number of labeled nuclei in the remaining kidney increased by factors of about 4 and 2.5 in the cortex and the medulla, respectively. Adrenalectomy moderately decreased the hyperplastic response of the cortex of the remaining kidney, but increased still further the labeling index of the medulla. By five days after unilateral nephrectomy of rats with intact adrenal glands, neither the cortex nor the medulla of the remaining kidney exhibited a marked hyperplastic response. In adrenalectomized animals, also, unilateral nephrectomy caused only slight increases in the labeling indices of the cortex and the medulla of the remaining kidney.