ABSORPTION OF BILIARY THYROXINE FROM LOOPS OF SMALL INTESTINE

Abstract

The absorption of labelled thyroxine and its glucuronide conjugate from loops of small intestine has been studied in rats. Free thyroxine was found to be more readily absorbed than its conjugate, suggesting that formation of the conjugate by the liver facilitates excretion of the hormone. No difference was found between the rate of absorption of these materials from loops prepared in cold-acclimated rats and from those prepared in warm-acclimated rats. Labelled D-thyroxine added to bile was found to be absorbed as readily as added L-thyroxine.