Vasopressin release in the spontaneously hypertensive rat

Vasopressin (antidiuretic hormone, ADH), release in response to hemorrhage was studied in spontaneously hypertensive rats (SHR), Kyoto-Wistar rats (KWR), and Wistar rats (WR). The rats were anesthetized with pentobarbital sodium and ADH concentration was measured before and after three successive hemorrhages at 15 min intervals. The blood samples for radioimmunoassay (RIA) of ADH were collected from the external jugular vein. The ADH release in response to hemorrhage was significantly reduced in debuffered WR (carotid and aortic baroceptors and atrioventricular receptors deafferented), intact KWR and intact SHR when compared to the intact WR.