Metabolic clearance rate of immunoreactive vasopressin in man

Abstract. Metabolic clearance of synthetic arginine vasopressin (AVP) has been measured in sixteen healthy subjects and ten uraemic patients on maintenance haemodialysis. Plasma AVP was measured using a specific radioimmunoassay at different intervals after a single injection of 2 μg AVP. The theoretical curve which fitted best with the disappearance curve was the sum of two exponentials in twenty-two subjects and of three exponentials in the other four. Metabolic clearance rate and the volume of fast initial distribution were 287·1 ml min^-1 (m²)^-1 and 219·3 ml/kg b.w., respectively, in normal subjects. Metabolic clearance rate was considerably lower in the uraemic group. This emphasizes the role of kidneys in the degradation of AVP and may account, at least in part, for the higher basal plasma value of this hormone observed in uraemic patients.