title: Thyroid hormone kinetics: improved method for quantitative separation and measurement of the various radioiodothyronine injection.
abstract: An accurate and reproducible method for measurement of radioactive species in blood after in vivo injection of labelled iodothyronines is described. By extraction with high-affinity antisera, radioactive reverse T3 and T3 are separated from serum quantitatively. Radioiodide is quantitatively separated from radio-thyronine species and serum proteins by Sephadex G50 filtration. The residual mixture of radio-T4 and iodoprotein is quantitatively resolved by ion-exchange adsorption. Minimal misclassification of radiospecies occurs, and can be corrected for. Mean recoveries of various radiospecies added to serum were: radioiodide 98.9%, radio-rT3 87.6%, radio-L-T3 94.5%, radio-T4 98.0% and radioiodoprotein 94.5%. The performance of the method is superior to that of chemical methods such as trichloracetic acid precipitation, ion-exchange or alkaline Sephadex extraction, and chromatographic separation.
mesh_terms: D002850:Chromatography, Gel; D007457:Iodine Radioisotopes; D011863:Radioimmunoassay / Q000379:methods; D013970:Thyronines / Q000097:blood*; D014284:Triiodothyronine / Q000097:blood*
chemical_list: D007457:Iodine Radioisotopes; D013970:Thyronines; D014284:Triiodothyronine