Vitamin-D-induced hypercalcaemia and its effect on serum gastrin, gastrin cells and antral gastrin in parathyroidectomized rats.

Nineteen rats were parathyroidectomized by electrocauterization, resulting in pronounced hypocalcaemia. Seven of these rats were then given vitamin D3 in a dose causing hypercalcaemia, while 7 received a dose which normalized serum calcium and 5 received no vitamin D. Ten further animals were sham-operated and were not given any extra vitamin D. The experimental period was 16 weeks. No significant differences in serum gastrin values were found between the different groups. Quantitative studies of the antral gastrin cells showed no difference in the number of gastrin cells per unit volume or unit segment between the different groups of vitamin-D-treated animals and sham-operated animals. However, the number of gastrin cells per unit segment was significantly higher in the hypocalcaemic animals than in the sham-operated animals, as a result of an increase in mucosal thickness. The amount of antral mucosal gastrin did not differ between the different groups. Thus the results of this study indicate that experimentally induced hypercalcaemia in parathyroidectomized rats does not influence the serum gastrin, the number of gastrin cells or antral gastrin.