EFFECT OF CCK-B GASTRIN RECEPTOR ANTAGONIST ON PEPSINOGEN-PRODUCING CELLS DURING OMEPRAZOLE TREATMENT

The present study investigated the effect of long-term treatment with omeprazole on pepsinogen-producing cells and examined whether the sele ctive CCK-B/gastrin receptor antagonist was able to prevent the omepra zole-induced changes, if occurred, in rat stomach. Rats were treated w ith omeprazole and/or the CCK-B/gastrin receptor antagonist for 28 day s. As a result, omeprazole markedly reduced mucosal pepsinogen activit y and its mRNA concentration in rat stomach. Morphologically, in fundi c glands omeprazole drastically decreased the proportion of mature chi ef cells and reciprocally increased that of immature chief cells which were positive for class III mucin. These effects of omeprazole were a ttenuated by an addition of the CCK-B/gastrin receptor antagonist. Our results suggest that omeprazole retards the differentiation of chief cells in fundic mucosa probably through hypergastrinemia in adult rat. (C) 1995 Academic Press, Inc.