Pancreatic enzyme secretion mediated by novel peptide: monitor peptide hypothesis.
A new model is proposed for pancreatic enzyme secretion in response to food protein intake in rats. We have found a novel peptide in rat bile-pancreatic juice, which exhibits a trypsin-sensitive, cholecystokinin (CCK)-releasing activity. The amino acid sequence of the peptide purified from rat bile-pancreatic juice is very similar to that of a conservative region in pancreatic secretory trypsin inhibitor (PSTI). The peptide loses its CCK-releasing activity during trypsin digestion, but food protein intake prevents this trypsin digestion. Results of a reconstitution experiment indicate that pancreatic enzyme secretion in response to food protein intake only occurs as a result of interaction between trypsin and our purified peptide. Also, a peptide-specific antibody abolished the response. These findings lead us to hypothesize that this peptide acts as an intraduodenal mediator for CCK release in response to food protein intake.
Iwai
K
K
Department of Food Science and Technology, Faculty of Agriculture, Kyoto University, Japan.
Fushiki
T
T
Fukuoka
S
S
D000595:Amino Acid Sequence; D000818:Animals; D000918:Antibody Specificity; D001285:Atropine / Q000494:pharmacology; D002766:Cholecystokinin / Q000378:metabolism; D004044:Dietary Proteins / Q000276:immunology; D008969:Molecular Sequence Data; D010179:Pancreas / Q000201:enzymology*; D010189:Pancreatic Juice / Q000032:analysis; D010455:Peptides / Q000032:analysis / Q000302:isolation & purification / Q000378:metabolism*; D051381:Rats; D014357:Trypsin / Q000494:pharmacology
D004044:Dietary Proteins; D010455:Peptides; D001285:Atropine; D002766:Cholecystokinin; D014357:Trypsin