HYPERCHOLECYSTOKININEMIA PRODUCED BY PANCREATICOBILIARY DIVERSION CAUSES GASTRIN-LIKE EFFECTS ON ENTEROCHROMAFFIN-LIKE CELLS IN THE STOMACH OF RATS SUBJECTED TO PORTACAVAL SHUNTING OR ANTRECTOMY

Gastrin and possibly cholecystokinin (CCK) control the activity and growth of the histamine-containing endocrine cells, the enterochromaffin-like (ECL) cells, in the oxyntic mucosa of the rat. Portacaval shunting (PCS) is known to activate the ECL cells through as yet unknown mechanisms. PCS also exaggerates the ECL cells' response to gastrin, whereas antrectomy causes hypotrophy and hypoplasia of the ECL cells. A recent study showed that the ECL cells failed to respond to sustained hyperCCKemia caused by pancreaticobiliary diversion (PBD). In the present study we investigated whether PBD-produced hyperCCKemia influenced the effects of PCS or antrectomy on the ECL cells. The results show 1) that hyperCCKemia raised the histidine decarboxylase (HDC) activity of the ECL cells in PCS rats but not in control rats, and the CCK-A receptor blockade failed to prevent the enzyme activation; and 2) that PBD prevented the ECL cell hypoplasia and the decrease in HDC activity induced by antrectomy. The findings suggest that under special circumstances endogenous CCK may stimulate the ECL cells.