The isolation of thyrocalcitonin and a study of its effects in the rat

Abstract

The thyroid secretes a polypeptide hormone (thyrocalcitonin) which is effective in lowering plasma calcium and phosphate. The hormone can be extracted from the thyroid of the rat, dog, pig, goat, ox and monkey. The isolation of the hormone from pig thyroid by a combination of salt fractionation and gel filtration is described. One microgram of the pure material is very active in the rat. Thyrocalcitonin remains effective after parathyroidectomy, after nephrectomy, after over-dosage with vitamin D, during vitamin D deficiency, and during calcium or magnesium deficiency. Its action is not prevented by prior administration of actinomycin D. A single injection does not change soft tissue calcium but infusion for 12 h lowers cardiac muscle calcium. It is concluded that this new thyroid hormone acts on bone and that it probably plays an important role in normal physiology.