3,5-diiodotyrosine excretion in human urine in individuals of differing thyroidal status

✍ Scribed by M. N. Mohammed; M. Farmer; D. B. Ramsden

• Publisher: John Wiley and Sons
• Year: 1983
• Tongue: English
• Weight: 408 KB
• Volume: 10
• Category: Article
• ISSN: 1076-5174
• DOI: 10.1002/bms.1200100906

✦ Synopsis

The urinary excretion of 3,5-diiodotyrosine was determined in euthyroid, hypothyroid and hyperthyroid individuals using a sensitive gas chromatographic mass spectrometric assay. This involved a multi-step extraction of the amino acid from urine (mean efficiency 28f 5.7%) then conversion to the N,O-diheptafluorobutyryl methyl ester. The fragmentation of the derivative is discussed. Although the mean excretions h; the two pathological states were significantly different from that of euthyroid individuals (P C 0.01 in both instances) there was considerable overlap with the normal range.

Step I: Urine (20ml) was acidified to pH 1 with 5.6 M HCl and submitted to cation-exchange chromatography on Dowex 50 (50 x 12-400) which was eluted successively with 6 ml of distilled water and 4 ml