CK-independent increases in pancreatic secretion induced by dietary protein in chronic BPJ-diverted rats.
Previously, we demonstrated that, in rats with chronic bile-pancreatic juice (BPJ) diversion, pancreatic enzyme secretion was increased after feeding animals a 25% casein fat-free diet. We determined whether cholecystokinin (CCK) or the cholinergic pathway is associated with the response of pancreatic secretion after protein ingestion in the diverted rats, using a potent CCK antagonist, MK-329 or FK-480, and a cholinergic blocker, atropine. Secretion rates of chymotrypsin and trypsin in the fasting state were very high 7 days after a BPJ diversion, and the hypersecretion of the proteases was markedly reduced with an injection of MK-329, FK-480, or atropine and was further reduced by combined injection of FK-480 and atropine. The lowered secretion of the proteases in CCK-antagonized rats was increased after oral feeding of a protein diet and after a duodenal instillation of some protein sources, especially hydrolysate of guanidinated casein (HGC). The CCK-independent increases by HGC instillation are completely depressed by atropine. In rats treated with only atropine, the lowered secretion tended to be increased by a duodenal instillation of HGC. Increases in secretion after an administration of the protein source in CCK-antagonized rats were not affected by bestatin, an inhibitor of brush-border peptidases. We conclude that the stimulatory effects of dietary protein on the pancreatic enzyme secretion partially do not depend on CCK in chronic BPJ-diverted rats and that the CCK-independent increase is atropine sensitive.
Hara
H
H
Department of Bioscience and Chemistry, Faculty of Agriculture, Hokkaido University, Sapporo, Japan.
Nishi
T
T
Narakino
H
H
Kasai
T
T
D000818:Animals; D001285:Atropine / Q000494:pharmacology; D001570:Benzodiazepinones / Q000494:pharmacology; D001646:Bile / Q000378:metabolism; D002766:Cholecystokinin / Q000037:antagonists & inhibitors / Q000378:metabolism*; D020109:Devazepide; D004032:Diet; D006727:Hormone Antagonists / Q000494:pharmacology; D007211:Indoles / Q000494:pharmacology; D008297:Male; D010179:Pancreas / Q000378:metabolism*; D010189:Pancreatic Juice / Q000378:metabolism*; D011506:Proteins / Q000008:administration & dosage*; D051381:Rats; D017207:Rats, Sprague-Dawley
D001570:Benzodiazepinones; D006727:Hormone Antagonists; D007211:Indoles; D011506:Proteins; C082966:FR 120480; D001285:Atropine; D002766:Cholecystokinin; D020109:Devazepide