Radioimmunoassay of Arginine Vasopressin in Human Plasma and Urine, a Resin Microcolumn Method

Abstract

A new method was developed for the estimation of arginine vasopressin (AVP) in plasma and urine. Samples Were extracted by a microcolumn of resin and assayed radioimmunologically using a highly sensitive antiserum to AVP. Ion-exchange resin, CG–50, H+ form, packed in a small column (diameter 4 mm, height 6 mm), was proved effective to remove the interfering substances and to concentrate the AVP in the sample. The application of 80% acid acetone successive to diluted HC1 brought about a consistent recovery of AVP from the resin column. Recoveries were 66.4±8.5% for plasma and 85.4±9.7% for urine. In normal subjects plasma AVP levels were 3.9±0.3 pg/ml (mean±S.D.) in ambulatory states, 4.9±0.6 after overnight fast, and 0.4 ±0.2 after water loading. High levels of 2.0-24.2 pg/ml were obtained in patinents with syndrome of inappropriate secretion of ADH (SIADH), low values of 0–1.8 pg/ml in diabetes insipidus. Urinary excretions of AVP were 117.4± 59.4 ng/24 hr (mean±S.D.) in normal controls, 191 ±177.0/24 hr in SIADH, and 17.0±12.0/24 hr in diabetes insipidus. © 1980, Tohoku University Medical Press. All rights reserved.