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Stimulation of rat parietal cell function by histamine and GLP-1-(7-36) amide is mediated by Gs alpha

Item Type:Article
Title:Stimulation of rat parietal cell function by histamine and GLP-1-(7-36) amide is mediated by Gs alpha
Creators Name:Schmidtler, J. and Dehne, K. and Offermanns, S. and Rosenthal, W. and Classen, M. and Schepp, W.
Abstract:It was the aim of the present study to determine in rat parietal cells whether Gs alpha, the stimulatory subunit of adenylate cyclase, mediates adenosine 3',5'-cyclic monophosphate (cAMP)-dependent parietal cell function in response to histamine and glucagon-like peptide 1 (GLP-1)-(7-36) amide. Cytoplasmic membrane from enriched (83 +/- 5%) rat parietal cells were incubated for 30 min with 30 microCi/ml [32P]NAD+ and 40 micrograms/ml preactivated cholera toxin (CT), a pharmacological tool for activation of Gs alpha. Subsequent sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and autoradiography revealed [32P]ADP ribosylation of Gs alpha represented by three proteins with molecular masses ranging from 42 to 45 kDa. In intact parietal cells, CT (10(-12)-10(-8) M) caused marked stimulation of [14C]aminopyrine accumulation and cAMP production confirming the functional importance of Gs alpha in regulation of H+ production. Identical membrane preparations were preincubated (2 h, 4 degrees C) in parallel with and without RM/1, a rabbit polyclonal anti-Gs alpha-antibody. Subsequently, adenylate cyclase was stimulated by histamine, GLP-1-(7-36) amide, CT, or forskolin. At a 1:10 dilution, the antiserum completely abolished adenylate cyclase activity in response to maximal concentrations of histamine, GLP-1-(7-36) amide, and CT while reducing forskolin stimulation by only 22.0 +/- 4.9%. At 1:50, RM/1 reduced responses to histamine, GLP-1-(7-36) amide and CT by 20-30% but failed to inhibit forskolin-stimulated enzyme activity. At 1:100, the antiserum was ineffective versus all stimuli.(ABSTRACT TRUNCATED AT 250 WORDS)
Keywords:Adenosine Diphosphate, Adenylate Cyclase, Aminopyrine, Cell Membrane, Cell Separation, Cells, Cultured, Cholera Toxin, Cyclic AMP, Drug Dose-Response Relationship, Polyacrylamide Gel Electrophoresis, Forskolin, GTP-Binding Proteins, Glucagon, Glucagon-Like Peptide 1, Glucagon-Like Peptides, Histamine, Kinetics, Molecular Weight, Gastric Parietal Cells, Peptide Fragments, Animals, Rats
Source:American Journal of Physiology
Publisher:American Physiological Society
Number:5 Pt 1
Page Range:G775-G782
Date:May 1994
Official Publication:http://ajpgi.physiology.org/cgi/content/abstract/266/5/G775
PubMed:View item in PubMed

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