title: Stimulation of rat parietal cell function by histamine and GLP-1-(7-36) amide is mediated by Gs alpha.
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)
authors.affiliation: Department of Internal Medicine II, Technical University of Munich, Germany.
authors.forename: J
authors.initials: J
authors.lastname: Schmidtler
authors.forename: K
authors.initials: K
authors.lastname: Dehne
authors.forename: S
authors.initials: S
authors.lastname: Offermanns
authors.forename: W
authors.initials: W
authors.lastname: Rosenthal
authors.forename: M
authors.initials: M
authors.lastname: Classen
authors.forename: W
authors.initials: W
authors.lastname: Schepp
mesh_terms: D000244:Adenosine Diphosphate / Q000378:metabolism; D000262:Adenylyl Cyclases / Q000378:metabolism; D000632:Aminopyrine / Q000378:metabolism; D000818:Animals; D002462:Cell Membrane / Q000378:metabolism; D002469:Cell Separation / Q000379:methods; D002478:Cells, Cultured; D002772:Cholera Toxin / Q000494:pharmacology; D005576:Colforsin / Q000494:pharmacology; D000242:Cyclic AMP / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004591:Electrophoresis, Polyacrylamide Gel; D005260:Female; D019204:GTP-Binding Proteins / Q000302:isolation & purification / Q000378:metabolism*; D005934:Glucagon; D052216:Glucagon-Like Peptide 1; D004763:Glucagon-Like Peptides; D006632:Histamine / Q000494:pharmacology*; D007700:Kinetics; D008970:Molecular Weight; D010295:Parietal Cells, Gastric / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D010446:Peptide Fragments / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar
chemical_list: D010446:Peptide Fragments; D000632:Aminopyrine; C061970:glucagon-like peptide 1 (7-36); D005576:Colforsin; D000244:Adenosine Diphosphate; D004763:Glucagon-Like Peptides; D006632:Histamine; D052216:Glucagon-Like Peptide 1; D005934:Glucagon; D002772:Cholera Toxin; D000242:Cyclic AMP; D019204:GTP-Binding Proteins; D000262:Adenylyl Cyclases