AMINOPEPTIDASE ACTIVITY IN FOETAL RAT PARATHYROIDS AND ITS INHIBITION BY VITAMIN D-INDUCED HYPERCALCAEMIA IN THE MOTHER RAT

Abstract
Previous investigations have suggested that there is a close correlation between the aminopeptidase activity in rat parathyroids and the production and secretion of parathyroid hormone. The present investigation demonstrates that parathyroids of rat foetuses 16, 19 and 22 days old have a high aminopeptidase activity. Vitamin D-induced hypercalcaemia in the mother rat reduces the aminopeptidase activity, parathyroid volume and mitotic rate in the parathyroids of 22 days old rat foetuses. The results of the present investigation support the view that the foetal rat parathyroids function from the 16th day of gestation and that induced hypercalcaemia of the pregnant rat inhibits this function.