Evidence against autocrine feedback regulation of cholecystokinin secretion in man.
To determine whether exogenous cholecystokinin (CCK) inhibits endogenous CCK release, cholecystokinin-8S (CCK-8S) was infused intravenously during continuous intraduodenal stimulation of endogenous CCK by a meal. CCK was measured in plasma by 2 region-specific radioimmunoassays employing antibodies T204 and 1703. AB T204 binds to carboxy-terminal CCK peptides containing the sulphated tyrosyl region, including CCK-8S, and AB 1703 to carboxy-terminal CCK peptides containing at least 14 amino acid residues. Meal-stimulated plasma CCK concentrations remained elevated during the entire infusion period. CCK-8S infusion further increased meal-stimulated plasma CCK concentrations, when measured with AB T204, while meal-stimulated plasma CCK concentrations were not suppressed by CCK-8S infusion, when measured with AB 1703. It is concluded that meal-stimulated endogenous CCK release is not affected by the effects of intravenously administered CCK-8S. These data suggest that autocrine feedback regulation of CCK release is not operative in man.
Jebbink
M C
MC
Department of Gastroenterology, University Hospital of Leiden, The Netherlands.
Jansen
J B
JB
Mooy
D M
DM
Schouten
C M
CM
Lamers
C B
CB
D000328:Adult; D002766:Cholecystokinin / Q000097:blood / Q000378:metabolism* / Q000494:pharmacology; D004435:Eating / Q000502:physiology*; D005246:Feedback / Q000502:physiology; D006801:Humans; D007262:Infusions, Intravenous; D011863:Radioimmunoassay
D002766:Cholecystokinin