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.
To elucidate this discrepancy.
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.
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.
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).
*Department of Clinical Physiology, Tokyo Metropolitan Institute of Gerontology, Tokyo; †Department of Medicine, Social Insurance Inatsuki Hospital, Fukuoka; ‡Department of Pathology, Kurume University, School of Medicine, Kurume; and §Department of Gastroenterology, National Kyushu Cancer Center, Fukuoka, Japan
Manuscript received June 8, 2001;
revised manuscript accepted October 11, 2001.
Address correspondence and reprint requests to Dr. Kyoko Miyasaka, Department of Clinical Physiology, Tokyo Metropolitan Institute of Gerontology, 35-2 Sakaecho Itabashiku, Tokyo-173-0015, Japan. E-mail: email@example.com