Sensitive Bioassay Method for Measuring Antidiuretic Hormone in Mammalian Plasma

Abstract

Rats are rendered unconscious with ethamol, placed under a constant water load, and are given intravenous injections of all standards and unknowns. The change in specific gravity of the rat urine expressed as antidiuretic index is used as the criterion of potency. Dog plasma had a significantly increased titer of antidiuretic hormone both following hemorrhage and following intracarotid infusion of hypertonic NaCl solution. The method appears to possess a high degree of sensitivity since small dose changes of reference vasopressin or small changes in endogenous circulating ADH, can be detected.