Experimental Hyperparathyroidism from Multiple Isologous Parathyroid Transplants: Homeostatic Effect of Simultaneous Thyroid Transplants11

Abstract

The intramuscular transplantation of 20, 40 or 80 isologous parathyroid glands into strictly inbred adult rats invariably resulted in a persistent hypercalcemia and eventual formation of calcium phosphate urinary calculi[long dash]an apparently obligatory endogenous hyperparathyroidism. The simultaneous transplantation, along with the parathyroids, of matching numbers of isologous thyroid lobes enabled the recipients to reduce circulating Ca levels to the upper limits of normal and greatly reduced the incidence of urinary calculi. It is concluded that the parathyroid of the rat is unable to reduce its secretion of parathormone below a certain basal level, even though perfused with hypercalcemic blood. Further, the findings argue against the presence of any effective Ca-lowering secretion from the parathyroid itself unless it be a thyro-calcitonin-releasing factor with activity mediated by thyroid tissue.