Amylase secretion from dispersed human pancreatic acini: neither cholecystokinin a nor cholecystokinin B receptors mediate amylase secretion in vitro.
BACKGROUND
In humans, cholecystokinin (CCK) stimulates pancreatic secretion, and CCK-A receptor antagonists prevent it in vivo. However, the human pancreas has been reported to express mainly CCK-B receptors.


OBJECTIVE
To elucidate this discrepancy.


METHODS
We prepared dispersed acini from human pancreas and examined whether various doses of CCK stimulated the release of amylase, in comparison with the effects of neuromedin C, carbamylcholine, and secretin.


RESULTS
Human pancreatic acini did not respond to any dose of CCK or secretin. Amylase release was stimulated by carbamylcholine and neuromedin C dose-dependently and was inhibited by respective antagonists. The localizations of CCK receptors in the human duodenum were determined. High concentrations of CCK-A receptors were detected in the mucosa as well as in smooth muscle of the duodenum by microautoradiography.


CONCLUSIONS
In conclusion, human pancreatic acinar cells are responsible for carbamylcholine and neuromedin C but not for secretin. Neither CCK-A nor CCK-B receptor mediates amylase release from human pancreatic acini in vitro. Pancreatic secretion in humans in vivo may be regulated indirectly by CCK (via CCK-A receptors).
Miyasaka
Kyoko
K
Department of Clinical Physiology, Tokyo Metropolitan Institute of Gerontology, Tokyo, Japan. miyasaka@tmig.or.jp
Shinozaki
Hirotsugu
H
Jimi
Atsuo
A
Funakoshi
Akihiro
A
D000681:Amylases / Q000187:drug effects / Q000378:metabolism*; D001345:Autoradiography; D001667:Binding, Competitive; D001839:Bombesin / Q000494:pharmacology; D002217:Carbachol / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004386:Duodenum / Q000378:metabolism; D005260:Female; D006801:Humans; D007457:Iodine Radioisotopes; D008297:Male; D008854:Microscopy, Electron; D008875:Middle Aged; D010179:Pancreas / Q000378:metabolism* / Q000473:pathology / Q000648:ultrastructure; D010446:Peptide Fragments / Q000494:pharmacology; D043886:Receptor, Cholecystokinin A; D043887:Receptor, Cholecystokinin B; D011949:Receptors, Cholecystokinin / Q000502:physiology; D012633:Secretin / Q000494:pharmacology; D012844:Sincalide / Q000378:metabolism / Q000494:pharmacology
D007457:Iodine Radioisotopes; D010446:Peptide Fragments; D043886:Receptor, Cholecystokinin A; D043887:Receptor, Cholecystokinin B; D011949:Receptors, Cholecystokinin; D012633:Secretin; C040794:neuromedin C; D002217:Carbachol; D000681:Amylases; D012844:Sincalide; D001839:Bombesin