EFFECT OF PROGESTERONE ON ADRENOCORTICAL HORMONE SECRETION IN NORMAL AND HYPOPHYSECTOMIZED RATS

SUMMARY In intact male rats fed on a normal diet, the subcutaneous administration of progesterone for 4·5 days resulted in a significant increase in the aldosterone secretion rate and a significant decrease in the corticosterone secretion rate as measured by the secretion of these hormones into adrenal vein blood of anaesthetized animals. In hypophysectomized rats the administration of progesterone for 5·5 days resulted in a significant increase in aldosterone secretion and a small, non-significant, decrease in the rate of corticosterone secretion. It is concluded that progesterone may influence the rate of secretion of aldosterone in pregnancy and that the mechanism by which this is achieved probably does not involve the pituitary gland.