title: Ouabain suppresses ATP elevation in response to fuel secretagogues in pancreatic islets.
abstract: The alterations of the ATP concentration in response to fuel secretagogues such as glucose, glyceraldehyde, and ketoisocaproate (KIC) were investigated in a single islet. The intraislet ATP concentration was transiently elevated and then decreased to a level slightly higher than basal. To asses the ATP content under conditions of reduced ATP consumption, the Na-K pump blocker ouabain was used. The elevation of ATP concentration was found unexpectedly to be suppressed under ouabain in the islet, even when incubated with any of the secretagogues. High glucose did not elevate the intracellular creatine phosphate during incubation with ouabain. Since the suppression rate for the intraislet ATP elevation was considerably smaller with KIC than with glyceraldehyde and glucose, we conclude that ouabain inhibits ATP production, at least in part, in the glycolytic pathway through a feedback mechanism.
authors.affiliation: Department of Metabolism and Clinical Nutrition, Kyoto University Faculty of Medicine, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Tsuura
authors.forename: H
authors.initials: H
authors.lastname: Ishida
authors.forename: M
authors.initials: M
authors.lastname: Nishimura
authors.forename: S
authors.initials: S
authors.lastname: Fujimoto
authors.forename: M
authors.initials: M
authors.lastname: Kajikawa
authors.forename: Y
authors.initials: Y
authors.lastname: Seino
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism*; D000818:Animals; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005947:Glucose / Q000494:pharmacology; D005985:Glyceraldehyde / Q000494:pharmacology; D066298:In Vitro Techniques; D007515:Islets of Langerhans / Q000187:drug effects* / Q000378:metabolism*; D007651:Keto Acids / Q000494:pharmacology; D007700:Kinetics; D008297:Male; D010042:Ouabain / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D000254:Sodium-Potassium-Exchanging ATPase / Q000037:antagonists & inhibitors
chemical_list: D004791:Enzyme Inhibitors; D007651:Keto Acids; D005985:Glyceraldehyde; D010042:Ouabain; C013082:alpha-ketoisocaproic acid; D000255:Adenosine Triphosphate; D000254:Sodium-Potassium-Exchanging ATPase; D005947:Glucose