Preparation of 125I-labelled arginine vasopressin for radioimmunoassay.
Despite the common use of gel chromatography for separation of products from radioiodination of arginine vasopressin, reported specific activities of the material used as radioimmunoassay label cover a very wide range. We present evidence that, while the choice of iodination reducing agent is critical in the case of arginine vasopressin, the volume of the gel bed is almost certainly the major reason for this discordance. On a suitably large column essentially carrier-free mono and diiodinated arginine vasopressin are readily separated from other iodination products, and when the arginine vasopressin antiserum is primarily directed toward the three amino acid tail of the molecule, the diiodinated label can be successfully employed in a radioimmunoassay. This observation is of particular significance in arginine vasopressin radioimmunoassay, where a detection limit less than 1 fmol is required to distinguish subnormal from normal plasma concentrations.
W A
WA
Sadler
C P
CP
Wright
J H
JH
Livesey
D001127:Arginine Vasopressin / Q000032:analysis*; D002850:Chromatography, Gel; D002851:Chromatography, High Pressure Liquid; D007457:Iodine Radioisotopes; D007553:Isotope Labeling; D011863:Radioimmunoassay
D007457:Iodine Radioisotopes; D001127:Arginine Vasopressin