The Chemical Determination of Liothyronine and Thyroxine in Enzymic Hydrolysates of Pork Thyroid

Abstract

Maximum amounts of liothyronine and thyroxine were released from pork thyroid by the proteolytic action of erepsin and trypsin after incubation for 96 hr. at 39°. The iodinated thyronines were extracted from the hydrolysate with butanol, separated chromatographically, eluted from the paper and measured quantitatively by a chemical method in which the reduction of ceric ion by arsenious acid is catalysed by the iodine containing compounds. The iodine found in liothyronine and thyroxine accounted for 18 to 25 per cent of the total organic iodine in pork thyroid. It is postulated that pork thyroglobulin contains approximately 1 molar residue of liothyronine and 2 molar residues of thyroxine.