title: Distribution, blood transport, and degradation of antidiuretic hormone in man.
abstract: The distribution, blood transport, and metabolic clearance of physiological concentrations of antidiuretic hormone were studied in 10 hydrated normal subjects with radioiodinated arginine vasopressin (125I-AVP). At 37 degrees C no binding of 125I-AVP to plasma proteins could be demonstrated, but some metabolites were associated with plasma proteins. 125I-AVP was rapidly distributed into a space approximating the extracellular fluid volume. Metabolic breakdown products became demonstrable within minutes after injection. The mean metabolic clearance rate of 125I-AVP was 4.1 ml/min/kg and the mean plasma half-life 24.1 min. Renal clearance had a mean value of 80 ml/min and accounted for 27% of the total metabolic clearance. It is concluded that in man antidiuretic hormone circulates as a free (non-protein bound) peptide, diffuses readily into the extracellular fluid space, and is metabolized within minutes. A plasma half-life of 24 min is consistent with the duration of antidiuresis after hormone administration or release.
mesh_terms: D000328:Adult; D001127:Arginine Vasopressin / Q000097:blood / Q000378:metabolism* / Q000652:urine; D002854:Chromatography, Paper; D005260:Female; D006801:Humans; D007467:Iodoproteins; D008297:Male; D014667:Vasopressins / Q000031:analogs & derivatives*
chemical_list: D007467:Iodoproteins; D014667:Vasopressins; D001127:Arginine Vasopressin