The identification of 3,3', 5,5',-tetraiodothyroformic acid within the rat liver

Homogenized rat livers were extracted with organic solvents and the extracts converted into more readily volatile derivatives (trimethylsilylmethyl esters and permethyl esters). Combined g.l.c.-mass-spectrometric analysis identified the presence of tetraiodothyroformate. It is postulated that mitochondrial beta-oxidation of tetraiodothyropyruvate results in the formation of this apparently undescribed metabolite.