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DOI: 10.1055/s-2007-1009319
© Georg Thieme Verlag, Stuttgart · New York
Separation of Iodothyronines from Iodinated Metabolites in Serum from Reverse T3 Tracer Kinetic Studies in Man and Dog:
A Comparison of Two MethodsPublication History
1988
1989
Publication Date:
14 March 2008 (online)
![](https://www.thieme-connect.de/media/hmr/198912/lookinside/thumbnails/10.1055-s-2007-1009319-1.jpg)
Summary
Iodothyronine separation from free iodide and iodoalbumin in serial serum samples obtained from 7 human and 5 dog studies following intravenous injection of radiolabeled reverse triiodothyronine (reverse T3) was compared using acidified ammonium acetate/tetrahydrofuran (THF) elution from C-18 SEP-PAK cartridges or ethyl acetate/butanol (EAB) extraction. Both methods excluded > 98% free iodide and > 99% iodoalbumin from the iodothyronine fraction. Recovery of labeled reverse T3 was higher for the THF/SEP-PAK (79.4 ± 4.1%) than for the EAB method (43.2 ± 6.1%, P < 0.001), and intra-assay coefficients of variation were lower (2.1 ± 0.6% and 4.4 ± 2.0%, respectively, P < 0.001); HPLC analysis of iodothyronine fractions revealed a single peak co-migrating with injected tracer. The THF/SEP-PAK technique allowed use of larger serum samples at later time points. Serum disappearance curves derived from these two methods were highly correlated in all cases (r = 0.998, P < 0.001), as were fits of data to sums of exponentials and calculated serum kinetic parameters.
Key-Words
Iodothyronines - Reverse T3 Kinetics - Canine - Human