Renal and blood pressure changes in response to vasopressin antagonism in the New Zealand genetically hypertensive rat.

The effects of a mixed pressor and antidiuretic vasopressin antagonist on blood pressure and renal function have been investigated in New Zealand genetically hypertensive and normotensive rats. Vasopressin antagonism was associated with a diuresis, compensatory polydipsia and kaliuresis in both normotensive and hypertensive animals. Hypertensive animals alone exhibited a natriuresis and a fall in systolic blood pressure, which was associated with a reduction in water balance and plasma sodium compared with antagonist-treated normotensive animals. The data suggest that vasopressin may exert a long-term influence on blood pressure through renally rather than vascularly mediated effects.