Role of vasopressin in hypertension: studies using the Brattleboro rat

Plasma arginine vasopressin (AVP) levels were elevated in both one-kidney, one-clip [1K-1C) and two-kidney, one-clip (2K-1C) hypertensive Long-Evans rats. Homozygous Brattleboro rats with hereditary hypothalamic diabetes insipidus (DI), which are completely devoid of vasopressin, were made hypertensive using the 1K-1C Goldblatt models for renal hypertension. The 2K-1C DI rats developed hypertension at the same rate and to the same degree as normal 2K-1C hypertensive Long-Evans rats. The development of hypertension in 1K-1C DI rats was similar to the normal 1K-1C hypertensive Long-Evans rats. However, the absolute levels of systolic blood pressure reached were significantly less in the vasopressin-deficient rats. Treatment with 1-desamino-8-D-arginine vasopressin (DDAVP), the synthetic analogue of arginine vasopressin that has high antidiuretic but low pressor potencies, was associated with restoration of water balance in the volume-depleted DI rats and also restored blood pressure to hypertensive levels equivalent to the 1K-1C Long-Evans rats. These studies suggest that vasopressin is not essential for the development of experimental renal hypertension in rats but may contribute to the absolute levels of systolic blood pressure reached through its properties as an antidiuretic hormone.