Mechanisms of CCK regulation of monitor peptide mRNA expression in pancreatic acinar AR42J cells.
We explored the mechanism(s) by which cholecystokinin (CCK) stimulation of AR42J rat pancreatoma cells results in increased mRNA expression of a CCK-releasing peptide [monitor peptide (MP)]. With the use of a newly established reverse transcription-polymerase chain reaction assay system, CCK was shown to increase the level of MP mRNA by about ninefold. When protein synthesis was blocked by addition of cycloheximide, the MP mRNA level remained unchanged in the presence of CCK. Inhibition of transcription with actinomycin D resulted in a half-life for MP mRNA of approximately 17 h, and this rate remained unchanged after CCK treatment, suggesting that CCK may regulate the MP mRNA level by influencing gene transcription. A-23187, bombesin, substance P, and carbachol increased the MP mRNA level. CoCl(2) abolished actions of both CCK and A-23187 on MP mRNA expression. Dibutyryl-adenosine 3',5'-cyclic monophosphate, forskolin, secretin, and vasoactive intestinal polypeptide had no effect on MP mRNA expression. 12-O-tetradecanoylphorbol-13-acetate and phorbol 12,13-dibutyrate also failed to increase MP mRNA. It was therefore proposed that CCK stimulates MP mRNA expression of AR42J cells in a Ca2+-dependent and protein kinase C-independent manner.
Kinouchi
T
T
Department of Food Science and Technology, Faculty of Agriculture, Kyoto University, Japan.
Tsuzuki
S
S
Minami
C
C
Hayashi
Y
Y
Sugimoto
E
E
Fushiki
T
T
D000818:Animals; D002118:Calcium / Q000502:physiology; D002460:Cell Line; D002766:Cholecystokinin / Q000494:pharmacology*; D003513:Cycloheximide / Q000494:pharmacology; D003609:Dactinomycin / Q000494:pharmacology; D006133:Growth Substances / Q000235:genetics*; D007328:Insulin / Q000494:pharmacology; D036341:Intercellular Signaling Peptides and Proteins; D019384:Nucleic Acid Synthesis Inhibitors / Q000494:pharmacology; D010179:Pancreas / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D010187:Pancreatic Hormones / Q000235:genetics*; D016133:Polymerase Chain Reaction; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D012333:RNA, Messenger / Q000378:metabolism*; D051381:Rats; D013268:Stimulation, Chemical; D014158:Transcription, Genetic; D014359:Trypsin Inhibitor, Kazal Pancreatic
D006133:Growth Substances; D007328:Insulin; D036341:Intercellular Signaling Peptides and Proteins; D019384:Nucleic Acid Synthesis Inhibitors; D010187:Pancreatic Hormones; D011500:Protein Synthesis Inhibitors; D012333:RNA, Messenger; C504705:Spink1 protein, rat; D003609:Dactinomycin; D014359:Trypsin Inhibitor, Kazal Pancreatic; D002766:Cholecystokinin; D003513:Cycloheximide; D002118:Calcium