CIRCULATING PANCREASTATIN IS A MARKER FOR THE ENTEROCHROMAFFIN-LIKE CELLS OF THE RAT STOMACH

Background/Aims: Peptides of the chromogranin family occur in peptide hormone-producing cells throughout the body. One source of such peptid es is the enterochromaffin-like (ECL) cells, which constitute the pred ominant population of endocrine cells in the fundus (the acid-producin g part) of the rat stomach. The purpose of this study was to examine w hether ECL cells, which are controlled by gastrin, represent a major s ource of circulating pancreastatin, a fragment of chromogranin A. Meth ods: Rats underwent surgical procedures and treatments in which the EC L cells could be manipulated. The procedures included antrectomy, fund ectomy, and gastrectomy (and adrenalectomy), and the treatments includ ed fasting or feeding, gastrin-17 infusion, and administration of omep razole or ranitidine. The concentrations of pancreastatin-like immuner eactivity (LI) and gastrin in the serum were determined by radioimmuno assay. Results: The serum pancreastatin-LI concentration was lowered b y about 80% by fundectomy and gastrectomy; both of these procedures el iminated the ECL cell population. Adrenalectomy had no effect on the s erum pancreastatin-LI concentration. Gastrin infusion, which activates the ECL cells, promptly increased serum pancreastatin-LI concentratio n. Refeeding after fasting and administration of omeprazole or ranitid ine increased the serum pancreastatin-LI concentrations; these respons es were prevented by antrectomy. Conclusions: The concentration of cir culating pancreastatin-LI reflects the activity of the ECL cells and t he size of the ECL cell population in the rat stomach.