Serum calcitonin in hypergastrinaemia due to achlorhydria

The serum concentrations of immunoreactive gastrin and immunoreactive calcitonin were measured in 13 fasting patients with achlorhydria and pernicious anaemia and in 10 age- and sex-matched fasting control subjects. All patients had highly elevated concentrations of gastrin in serum (1468 +/- 336 pg/ml, mean "/- SEM). The mean concentration in the controls was 35.2 +/- 6.4 pg/ml. No difference in the concentration of calcitonin was found between the pernicious anaemia patients and the controls, the levels being 0.93 +/- 0.08 and 0.89 +/- 0.03 ng/ml, respectively. Suppression of endogenous gastrin secretion in 5 of the patients by intragastric acid administration was not accompanined by any decrease in calcitonin concentration in serum. The findings suggest that chronically elevated endogenous gastrin is without influence on calcitonin secretion.