The effect of vasopressin upon the vasculature of the isolated perfused rat kidney.

The timed uptake of (131)I-labelled human serum albumin was used as an index of regional perfusion in the isolated rat kidney.1. Arginine vasopressin in doses of 1, 5 and 10 muu./ml. of perfusate decreased papillary perfusion. Total renal perfusion was decreased only by the 5 muu. dose.2. Ornithine-8-vasopressin in doses of 5 and 10 muu./ml. of perfusate decreased papillary perfusion. Total renal perfusion was decreased only by the 10 muu. dose.3. When the relative viscosity of the perfusate was increased to a value of 2.0 from the control value of 1.7, both papillary perfusion and total renal perfusion were reduced.4. Arginine vasopressin further reduced papillary flow in kidneys perfused with high viscosity artificial plasma.