The degradation of thyroxine in sheep : A thesis submitted in partial fulfilment of the requirement for the Degree of Master of Science in the University of Canterbury

Abstract

Attempts were made to separate the conjugate of thyroxine found in the urine and bile of sheep from the wide range of other compounds found in these two mixtures. A number of chemical methods of identification of this compound were investigated to test their reliability and sensitivity. As no chemical system was found which was both reliable and sensitive, radio tracers in the form I¹³¹ thyroxine and I¹²⁵ thyroxine were used for the determination of iodine containing compounds . Paper chromatography with collidine water (100:35) in ammonia was found to be the most efficient method of identifying and separating indonated compounds, both from each other and other compounds in urine and bile. The major difficulty with paper chromatography is the small quantities which can be handled. Solvent extraction was found to be superior to ion exchange column chromatography for the initial separation of urine and bile. Not only could solvent extraction handle larger quantities, but the extract contained a higher proportion of iodonated compounds than found in the products of column chromatography . Liver suspensions were found to be able to convert some thyroxine to conjugate.The quantities were very small and the reaction did not follow the path of conventional conjugation reactions. Gas liquid chromatography could provide final identification of this compound if the sample could be produced with a high degree of purity and standards found for the gas liquid chromatography system .