Günther R, Carstens OC, Schmidt WE, Fölsch UR. Transient agonist-induced regulation of the cholecystokinin-A and cholecystokinin-B receptor mRNA levels in rat pancreatic acinar AR42J cells.
Pancreatology 2003;
3:47-54. [PMID:
12649564 DOI:
10.1159/000069142]
[Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/21/2001] [Accepted: 07/25/2002] [Indexed: 12/11/2022]
Abstract
BACKGROUND
CCK-8 and gastrin exert multiple effects in the gastrointestinal tract and the nervous system. Their actions are mediated via the G-protein coupled CCK-A and CCK-B receptors.
METHODS
Rat pancreatic acinar tumor AR42J cells express both CCK receptor subtypes. This cell line was used to characterize the agonist-dependent regulation of CCK-A and CCK-B receptor gene expression.
RESULTS
CCK-8 (10 nM) or gastrin (10 nM) reduced CCK-A receptor mRNA expression to 56% and 53%, respectively 2 h after hormonal exposure. In contrast, the level of CCK-B receptor gene expression was upregulated to 157% and 153%, respectively. These effects are most probably linked to the CCK-B receptor in AR42J cells. The phorbolester PMA (100 nM), a protein kinase C activator, downregulated CCK-A receptor expression but did not affect CCK-B receptor gene transcription. Activation of protein kinase A by forskolin (10 microM) or Bt(2)cAMP (100 microM) is not involved in the transient regulation of CCK receptor mRNA expression. Both elevated CCK-B and decreased CCK-A receptor mRNA expression returned to basal levels 6 h after continuous stimulation.
CONCLUSION
These results demonstrate that CCK-A and CCK-B receptor mRNA levels are differentially regulated by their agonists via distinct signal transduction mechanisms in AR42J cells.
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