Relationship between vitamin D deficiency, thyrocalcitonin, and parathyroid hormone

Abstract

The effects of thyrocalcitonin and parathyroid hormone on serum Ca and P concentrations were studied in vitamin D-deficient animals. Thyrocalcltonin was effective in lowering serum Ca, while parathyroid hormone was without effect on this parameter in vitamin D deficiency. The low serum Ca which resulted from thyrocalcitonin remained low for a long period of time in thyroparathyroidectomlzed rats, while in intact animals the effect of thyrocalcitonin was very much shorter. The response of serum Ca to thyrocalcltonin was reduced by concomitant administration of parathyroid hormone. Serum P was also decreased by thyrocalcitonln in vitamin D-deficient animals. The hyperphosphatemla caused by thyro-parathyroldectomy was reversed by administration of thyrocalcltonin both in vitamin D-deficient and vitamin D-fed animals.