Effects of adrenalectomy and of hypophysectomy on the development of sound-withdrawal hypertension

Female rats, initially 160–180 g, of a single inbred Wistar strain develop an hypertension reaching peak value at 4 weeks and stabilizing at a slightly lower level by the 6th week after transfer to a sound-proof semi-anechoic room (SPR). Blood corticosterone and deoxycorticosterone levels do not change significantly: urinary catecholamine excretion gradually decreases, and the rates of the urinary excretion of water and of Na+ in the first hour of water diuresis are depressed throughout the first week in the SPR. Adrenalectomy with salt maintenance, and hypophysectomy, prevent the development of this hypertension. Treatment with methyl prednisolone restores the ability of the adrenalectomized, but not of the hypophysectomized, rats to develop sound-withdrawal hypertension.