Method to estimate small amounts of L-triiodothyronine in D-triiodothyronine

✍ Scribed by Irving B. Eisdorfer; Alex Post

• Publisher: John Wiley and Sons
• Year: 1967
• Tongue: English
• Weight: 594 KB
• Volume: 56
• Category: Article
• ISSN: 0022-3549
• DOI: 10.1002/jps.2600560908

✦ Synopsis

One of the requirements for the use of D-triiodothyronine as a serum cholesterollowering agent is that it be essentially free of its optical isomer, L-triiodothyronine. A method for estimating small amounts of L-triiodothyronine in D-triiodothyronine is described. After removing any free triiodothyroacetic acid that may be present, the sample is reacted with stereospecific L-amino oxidase (from snake venom) to oxidize the L-triiodothyronine to triiodothyropyruvic acid. The triiodothyropyruvic acid is degraded to triiodothyroacetic acid, extracted, and chromatographed on paper to separate it from the unoxidized D-triiodothyronine. The final quantitative estimation is made by comparing the size and intensity of the colored spot, as visualized by an appropriate spray reagent, with those obtained from known mixtures of L-and D-triiodothyronine carried through the entire procedure. As little as 0.05 per cent L-triiodothyronine could be estimated in the various samples evaluated.