Preparation of exp 125 I-Labelled Thyroid Hormones for Use in Radioimmunoassay. Part of a Coordinated Programme on Quality Control of Techniques in-Vitro Assay of Thyroid-Related Hormones (Latin America). Final Report for the Peri

摘要

The primary objective was to prepare exp 125 I labelled thyroid hormones for use in radioimmunoassays. T sub 4 and T sub 3 of very high specific activity was obtained by just labelling T sub 2 . With a molar relation of T sub 2 : exp 125 I as 1:2 and Chloramine T: exp 125 I as 60:1 it was possible to produce T sub 4125 I of approximately 3,300 to 3,800 uc/ug and T sub 3125 I of 1,800 and 2,500 uc/ug with reaction times of 60'' to 90''. Simultaneous production from T sub 2 of both labelled T sub 4 and T sub 3 of high specific activity appears to be the best choice for routine radioimmunoassays. Various permutations of the molar relations between T sub 2 and exp 125 I and between chloramine T and exp 125 I it was possible to produce labelled T sub 3 and T sub 4 of varying degrees of specificities. The labelled products can be separated by sephadex G25 chromatography with good resolution. The separation is still improved if sephadex LH-20 is used. T sub 4 and T sub 3 of very high specific activity is preserved best for about a month in Cyst-PG-Alb. Low specific activity material can be preserved in the same medium for about 3 months. (Atomindex citation 16:001587)