EFFECT OF PIRENZEPINE ON GASTRIC ENDOCRINE CELL-KINETICS DURING LANSOPRAZOLE ADMINISTRATION

We studied the effect of pirenzepine on gastric secretion kinetics in rats in a hypochlorhydric state induced by lansoprazole, a proton pump inhibitor. Pirenzepine was administered intramuscularly at a dosage o f 20 mg/kg twice daily; and lansorprazole, subcutaneously at 50 mg/kg once daily, both every day for 4 weeks. After the 4-week treatment, se rum gastrin and plasma somatostatin levels were determined by radioimm unoassay. In addition, gastrin cells, somatostatin cells, and enteroch romaffin-like cells were immunostained and counted. Serum gastrin leve ls were elevated, and gastrin and enterochromaffin-like cell numbers i ncreased in the group on lansoprazole alone, compared with these value s in the control group (which received distilled water). In the group on the lansoprazole and pirenzepine combination, serum gastrin levels decreased, and gastrin and enterochromaffin-like cell numbers were sig nificantly decreased, compared with the respective variables in the gr oup on lansoprazole alone, while the number of somatostatin cells incr eased in the group on the combination. Plasma somatostatin levels did not vary significantly in any group. It was thus demonstrated that pir enzepine corrects the abnormal gastric secretion kinetics resulting fr om treatment with lansoprazole alone, such as hypergastrinemia and gas trin and enterochromaffinlike cell hyperplasia.