Possible Role and Mode of Action of Gastrin on Calcium Homeostasis in the Rat (41236)

Abstract

The hypocalcemic effect of gastrin and its possible mode of action were studied in rats. Gastrin (13 μg/100 g rat), injected intravenously led to a significant reduction in the plasma calcium concentrations. The release of endogenous gastrin by an intragastric phenylalanine instillation similarly led to a significant hypocalcemia in intact rat but not in antrectomized rat. Moreover, the protective role of endogenous gastrin against hypercalcemia induced by an intraduodenal infusion of CaCl2(10 mg/100 g rat) was demonstrated. Gastrin (50 μg/100 g rat) seems to have no influence on the net intestinal absorption of45Ca. The removal of45Ca from plasma was also unaffected by gastrin administration. The disappearance rate from plasma of45Ca administered 17 hr previously was compared in sham, thyroidectomized (TX) and parathyroid-auto transplanted rats receiving saline or gastrin. The faster rate of disappearance of plasma45Ca from plasma in gastrin-treated TX autoparathyroid-transplanted rats indicated the suppressive action of gastrin on the release of45Ca from as yet unknown source(s). © 1981, SAGE Publications. All rights reserved.