The effect of thyroxine on the movement of calcium and inorganic phosphate through the small intestine of the rat.

Abstract

SUMMARY Young female rats were given a daily injection of 1 mg. thyroxine/kg. body weight for 7 days. They were killed on the eighth day and the small intestine used for a study of the movement of radioactive calcium and inorganic phosphate. The everted sac technique was used. The results indicate that the passive movement of phosphate was depressed. Both the passive and active transport of calcium were also depressed. It is suggested that the transport of calcium and the transport of phosphate, whether active or passive, are related and that thyroxine affects a single site located perhaps at the basement membrane of the mucosa.