Effect of secretin on gastrin release from gastrinoma cells in vitro

Secretin appears to have a direct effect on gastrinoma cells, which results in a paradoxic increase in the serum gastrin level in patients with the Zollinger-Ellison syndrome. To evaluate this effect, gastrinoma cells were challenged with secretin in acute cell dispersion or after 2 weeks in culture. Acutely dispersed cells were incubated for 15 minutes or 3 hours with and without secretin 10(-6) mol/L. (sec). There was no significant difference in gastrin release between control and sec groups in the two acute incubation periods. At 15 minutes the control value was 47 +/- 1 and the sec value was 54 +/- 1 ng/ml, while at 3 hours the control value was 59 +/- 1 and the sec value was 61 +/- 1 ng/ml. In the cell culture preparation, secretin stimulated gastrin release at all doses (control 463 +/- 85, SEC 10(-10) mol/L 603 +/- 37, sec 10(-8) mol/L 706 +/- 37, sec 10(-6) mol/L 798 +/- 48 pg/ml ([p less than 0.05, Student t test]). These results indicate that secretin stimulates gastrin release directly from cultured gastrinoma cells in a dose-dependent manner but does not stimulate gastrin release from acute cell dispersion. This might be attributed partly to the recovery of secretin receptors in the cultured cells.