title: The generation of inositolglycan mediators from rat liver plasma membranes: the role of guanine nucleotide binding proteins.
abstract: The guanine nucleotide dependence for the generation of inositolglycan second messengers from rat liver plasma membranes has been investigated. Plasma membranes, when treated with insulin release a soluble mediator substance which activates pyruvate dehydrogenase (PDH). Guanosine 5'-[3-thio]triphosphate (GTP gamma S) was found to be as potent as insulin in stimulating mediator release. The stimulatory effects of GTP gamma S required the presence of magnesium and following preincubation of membranes with guanosine 5'-[2-thio]diphosphate (GDP beta S) the stimulation of mediator release by either insulin or GTP gamma S was blocked. The activation of PDH by mediator fractions produced in response to either insulin or GTP gamma S was abolished following treatment of the fractions with anti-inositolglycan antibodies. The significance of these observations with respect to the possible involvement of a regulatory guanine-nucleotide binding protein (G-protein) in the generation of insulin mediators is discussed.
authors.affiliation: Department of Pharmacology, University of Virginia Health Sciences Center, Charlottesville 22908.
authors.forename: E
authors.initials: E
authors.lastname: Kilgour
authors.forename: J
authors.initials: J
authors.lastname: Larner
authors.forename: G
authors.initials: G
authors.lastname: Romero
mesh_terms: D000255:Adenosine Triphosphate / Q000494:pharmacology; D000818:Animals; D000906:Antibodies; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D019204:GTP-Binding Proteins / Q000378:metabolism*; D006150:Guanine Nucleotides / Q000494:pharmacology*; D016244:Guanosine 5'-O-(3-Thiotriphosphate) / Q000494:pharmacology*; D007294:Inositol / Q000031:analogs & derivatives* / Q000276:immunology / Q000378:metabolism; D007328:Insulin / Q000494:pharmacology*; D007700:Kinetics; D008099:Liver / Q000378:metabolism*; D008297:Male; D011134:Polysaccharides / Q000276:immunology / Q000378:metabolism*; D011768:Pyruvate Dehydrogenase Complex / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D015290:Second Messenger Systems
chemical_list: D000906:Antibodies; D006150:Guanine Nucleotides; D007328:Insulin; D011134:Polysaccharides; D011768:Pyruvate Dehydrogenase Complex; C068698:inositol-glycan; D016244:Guanosine 5'-O-(3-Thiotriphosphate); D007294:Inositol; D000255:Adenosine Triphosphate; D019204:GTP-Binding Proteins