Luminal dietary protein, not amino acids, induces pancreatic protease via CCK in pancreaticobiliary-diverted rats.
We determined whether pancreatic adaptation to a high-protein diet depends on ingested protein in the intestinal lumen and whether such adaptation depends on a CCK or capsaicin-sensitive vagal afferent pathway in pancreaticobiliary-diverted (PBD) rats. Feeding a high-casein (60%) diet but not a high-amino acid diet to PBD rats increased pancreatic trypsin and chymotrypsin activities compared with those after feeding a 25% casein diet. In contrast, feeding both the high-nitrogen diets induced pancreatic hypertrophy in PBD rats. These pancreatic changes by the diets were abolished by treatment with devazepide, a CCK-A receptor antagonist. Protease zymogen mRNA abundance in the PBD rat was not increased by feeding the high-casein diet and was decreased by devazepide. Perivagal capsaicin treatment did not influence the values of any pancreatic variables in PBD rats fed the normal or high-casein diet. We concluded that luminal protein or peptides were responsible for the bile pancreatic juice-independent induction of pancreatic proteases on feeding a high-protein diet. The induction was found to be dependent on the direct action of CCK on the pancreas. Pancreatic growth induced by high-protein feeding in PBD rats may depend at least partly on absorbed amino acids.
Hara
H
H
Division of Applied Bioscience, Graduate School of Agriculture, Hokkaido University, Sapporo 060-8589, Japan. hara@chem.agr.hokudai.ac.jp
Ohyama
S
S
Hira
T
T
D000222:Adaptation, Physiological / Q000187:drug effects; D000596:Amino Acids / Q000008:administration & dosage / Q000494:pharmacology; D000818:Animals; D015904:Biliopancreatic Diversion; D002211:Capsaicin / Q000494:pharmacology; D002766:Cholecystokinin / Q000502:physiology*; D020109:Devazepide / Q000494:pharmacology; D004032:Diet; D004044:Dietary Proteins / Q000494:pharmacology*; D010450:Endopeptidases / Q000378:metabolism*; D006727:Hormone Antagonists / Q000494:pharmacology; D008297:Male; D010179:Pancreas / Q000187:drug effects / Q000201:enzymology* / Q000254:growth & development / Q000502:physiology; D051381:Rats; D017207:Rats, Sprague-Dawley
D000596:Amino Acids; D004044:Dietary Proteins; D006727:Hormone Antagonists; D002766:Cholecystokinin; D010450:Endopeptidases; D020109:Devazepide; D002211:Capsaicin