Effect of changes in serum calcium on secretin-stimulated serum gastrin in patients with Zollinger-Ellison syndrome.

This study was undertaken to determine whether or not the serum gastrin response to secretin in patients with Zollinger-Ellison syndrome is influenced by changes in serum calcium. After infusion of 50 mg/kg disodium ethylenediaminetetraacetate over 90 min in 7 patients with Zollinger-Ellison syndrome, increases in serum gastrin following administration of 1 CU/kg (Cu-clinical unit) secretin GIH (118 +/- 46 pg/ml) were lower than the response before the infusion (755 +/- 90 pg/ml; p less than 0.01). Before infusion of disodium ethylenediaminetetraacetate all 7 patients with Zollinger-Ellison syndrome had gastrin increases after secretin administration above 100 pg/ml, while after the infusion 4 of 7 patients had secretin-stimulated increases in serum gastrin below 100 pg/ml. Subsequent normalization of serum calcium by infusion of 3 mg/kg calcium over 15 min resulted in gastrin responses to secretin of greater than 100 pg/ml. Infusion of 10 mg/kg calcium over 120 min in 4 Zollinger-Ellison syndrome patients induced significant increases in secretin-stimulated serum gastrin from 660 +/- 180 to 1339 +/- 286 pg/ml (p = 0.005). This dose of calcium did not increase the gastrin response to secretin in 5 normogastrinemic and 2 hypergastrinemic control subjects. It was concluded that serum gastrin response to secretin in patient with Zollinger-Ellison syndrome is influenced by serum calcium concentrations.