Stryjek-Kaminska D, Piiper A, Caspary WF, Zeuzem S. Epidermal growth factor inhibits hormone- and fibroblast growth factor-induced activation of phospholipase C in rat pancreatic acini.
Peptides 1995;
16:123-8. [PMID:
7536322 DOI:
10.1016/0196-9781(94)00164-2]
[Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Epidermal growth factor (EGF) inhibits cholecystokinin-octapeptide-stimulated amylase release and inositol 1,4,5-trisphosphate (1,4,5-IP3) production in isolated rat pancreatic acini. In the present study, pancreatic acini were used to investigate the effect of EGF on amylase release and 1,4,5-IP3 production induced by secretagogues that activate either phospholipase C-beta (carbachol, bombesin) or phospholipase C-gamma [basic fibroblast growth factor (bFGF)]. The results show that EGF (100 ng/ml) inhibited bombesin (0.1 nM-1 microM)-induced amylase release almost completely. Similarly, the effect of EGF on carbachol-stimulated amylase release was substantial at submaximal (0.1 microM: 44% inhibition), maximal (1 microM: 75% inhibition), and supramaximal (100 microM: 33% inhibition) carbachol concentrations. EGF reduced amylase release at submaximal bFGF concentrations (0.1 nM: 40% inhibition), but not at supramaximal bFGF concentrations (1 and 10 nM). EGF decreased the peak increase of 1,4,5-IP3 in response to bombesin and carbachol (5 s after beginning of the incubation) and bFGF (15 s after beginning of the incubation) by 81 +/- 19%, 65 +/- 15%, and 56 +/- 18%, respectively. Receptor binding characteristics for secretagogues that activate phospholipase C were not influenced by coincubation with EGF excluding heterologous transmembrane receptor modulation. These results suggest that EGF inhibits the action of phospholipase C-beta- and gamma-isoenzyme-activating secretagogues in the exocrine pancreas by a postreceptor mechanism.
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