Regulation of Parathyroid Hormone Secretion<i>in Vitro:</i>Quantitative Aspects of Calcium and Magnesium Ion Control

Abstract

In studies of parathyroid hormone secretion in organ culture, the quantitative aspects of calcium and magnesium ion control were compared. The response of the glands in vitro paralleled their function in vivo, indicating that the system was a valid model for studying hormone regulation. There was a first-order relationship between hormone release and the total concentration of divalent cation (calcium plus magnesium); calcium and magnesium ions were equivalent in blocking the release of hormone. These observations emphasize the physiologic regulation of parathyroid hormone secretion by both calcium and magnesium ions and suggest the possibility of a cation-ligand interaction in or at the surface of the parathyroid cell. (Endocrinology88: 1477, 1971)