Effects of cholecystokinin and carbamylcholine on paneth cell secretion in mice: A comparison with pancreatic acinar cells

Abstract

Abstract To confirm whether the Paneth cells of mice (ICR, male, 10–12 weeks old) have the same secretory response to hormonal and cholinergic stimulation as do pancreatic acinar cells, ultrastructural changes of Paneth cells and pancreatic acinar cells 1 hr after administration of various doses of cholecystokinin (octapeptide, CCK‐8) and carbamylcholine were morphometrically assessed. After maximal (1.5 μg/kg intraperitoneally [i.p.]) and supramaximal (15 μg/kg, i.p.) stimulation by CCK‐8, pancreatic acinar cells showed, respectively, degranulation or disturbance of secretion (e.g., an increase in lysosome‐like bodies, aggregation of zymogen granules). The Paneth cells, however, were almost unchanged in the parameters examined. After carbamylcholine injection (1,000 μg/kg, subcutaneously [s.c.]), both pancreatic acinar cells and Paneth cells showed degranulation. Paneth cells sometimes developed large vacuoles, probably formed after massive exocytosis; such vacuoles were not observed in pancreatic acinar cells. It is suggested that Paneth cells and pancreatic acinar cells have different secretory responses. Paneth cell secretion, which possibly plays a role in controlling the intestinal bacterial mileu, may be stimulated by cholinergic rather than hormonal mechanisms.