Vasopressin in the Rat with Partial Nephrectomy-salt Hypertension

The role of vasopressin in the pathogenesis of partial ne-phrectomy (PN)-salt hypertension was examined in the rat. Hypertension was produced by reducing renal mass 70% and substituting 1% saline for drinking water 2 to 4 days after surgery. PN alone resulted in an increase in systolic blood pressure. Subsequent salt loading led to a further large increase in arterial pressure. On the second to third day after substitution of saline for drinking water, urinary vasopressin excretion (UADHV) was increased six-fold and the plasma vasopressin concentration was increased two and one-half-fold. UADHV) then fell to a level that was threefold greater than control values 5 days later. Although there was a marked stimulation of vasopressin release during the period of