[Radioimmunoassay of arginine vasopressin in human plasma]

A sensitive radioimmunoassay for human plasma arginine vasopressin was established. 125I-sAVP (1369mCi/mg) was first produced by the Iodogen method and could be used for up to one month in -25 degrees C storage. The sensitivity was 0.15 pg/tube. The sensitivity of the assay was 0.60 pg/ml, with a range of 0.6-11.0 pg/ml. The acetone-ethanol petroleum method was used to extract vasopressin from plasma samples, with a recovery rate of 75.6%. The intra- and inter-assay coefficients of variation were 9.8% and 16.8% respectively. Plasma vasopressin extraction was proved to be indispensible to the assay by virtue of its ability to minimize plasma protein interference. The physiological fluctuation of human plasma vasopressin with and without water intake was shown to be significant between normal adults and patients with neurogenic diabetes insipidus.