Effects of lectins on CCK-8-stimulated enzyme secretion and differentiation of the rat pancreatic cell line AR42J.
BACKGROUND
The peptide hormone cholecystokinin (CCK) plays an important role in the gastrointestinal tract. The rat pancreatic CCK receptor is a highly glycosylated membrane receptor that is able to bind to plant lectins such as wheat germ agglutinin (WGA) and Ulex europaeus agglutinin (UEA-I).


OBJECTIVE
We used both lectins to block this receptor for studying the pathophysiologic relevance of its oligosaccharide side chains. In the present study we investigated the influence of WGA and UEA-I on CCK-8-induced alpha-amylase secretion of the rat pancreatic tumor cell line AR42J, which expresses both CCK-A and CCK-B receptors.


RESULTS
Under the influence of WGA (25 microg/mL), the alpha-amylase release was reduced by 25% after 30 minutes compared with the hormone-stimulated controls. UEA-I (25 microg/mL) caused a reduction of 20%. The simultaneous application of the lectins with CCK antagonists L 364,718 or L 365,260 led to a reduction of secretion, but the assignment to CCK-A or CCK-B receptors was not possible.


CONCLUSIONS
In long-term studies, both lectins revealed no toxic or apoptosis-inducing effects. On the contrary, WGA showed an inhibitory effect on cell proliferation and led to improved differentiation of cells.
Mikkat
U
U
Department of Pathology, Faculty of Medicine, University of Rostock, Strempelstrasse 14, D-18055 Rostock, Germany.
Damm
I
I
Kirchhoff
F
F
Albrecht
E
E
Nebe
B
B
Jonas
L
L
D000818:Animals; D001570:Benzodiazepinones / Q000494:pharmacology; D002454:Cell Differentiation / Q000187:drug effects*; D002455:Cell Division / Q000187:drug effects; D020109:Devazepide / Q000494:pharmacology; D007700:Kinetics; D037102:Lectins / Q000494:pharmacology*; D008854:Microscopy, Electron; D010179:Pancreas / Q000201:enzymology* / Q000648:ultrastructure; D010190:Pancreatic Neoplasms; D010671:Phenylurea Compounds / Q000494:pharmacology; D037121:Plant Lectins; D051381:Rats; D043886:Receptor, Cholecystokinin A; D043887:Receptor, Cholecystokinin B; D011949:Receptors, Cholecystokinin / Q000037:antagonists & inhibitors / Q000502:physiology; D012844:Sincalide / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D014407:Tumor Cells, Cultured; D014909:Wheat Germ Agglutinins / Q000494:pharmacology; D000516:alpha-Amylases / Q000378:metabolism*
D001570:Benzodiazepinones; D037102:Lectins; D010671:Phenylurea Compounds; D037121:Plant Lectins; D043886:Receptor, Cholecystokinin A; D043887:Receptor, Cholecystokinin B; D011949:Receptors, Cholecystokinin; C036850:Ulex europaeus lectins; D014909:Wheat Germ Agglutinins; C058121:L 365260; D000516:alpha-Amylases; D020109:Devazepide; D012844:Sincalide