Chronic administration of bombesin stimulates antral gastrin cell proliferation in the rat.

Bombesin tetradecapeptide, administered in gelatin twice daily for 1 wk, significantly increased the antral gastrin content in rats by stimulating antral gastrin cell proliferation. The labeling index of gastrin cells after five daily injections of [3H]thymidine given during bombesin treatment was significantly enhanced as compared with controls, while no modification in the pattern of antral somatostatin cell labeling was revealed. Total antral gastrin cell population at the end of bombesin treatment also increased significantly. Morphometric measurements at the electron microscope level showed that the mean size of gastrin cell in the bombesin-treated group was the same as in the control group. The size of gastrin secretory granules and their number per cell did not change. The present findings demonstrate that chronic administration of bombesin induces gastrin cell hyperplasia in the rat.