title: Stoichiometric relationship between Na(+) ions transported and glucose consumed in human erythrocytes: Bayesian analysis of (23)Na and (13)C NMR time course data.
abstract: We examined the response of Na(+),K(+)-ATPase (NKA) to monensin, a Na(+) ionophore, with and without ouabain, an NKA inhibitor, in suspensions of human erythrocytes (red blood cells). A combination of (13)C and (23)Na NMR methods allowed the recording of intra- and extracellular Na(+), and (13)C-labeled glucose time courses. The net influx of Na(+) and the consumption of glucose were measured with and without NKA inhibited by ouabain. A Bayesian analysis was used to determine probability distributions of the parameter values of a minimalist mathematical model of the kinetics involved, and then used to infer the rates of Na(+) transported and glucose consumed. It was estimated that the numerical relationship between the number of Na(+) ions transported by NKA per molecule of glucose consumed by a red blood cell was close to the ratio 6.0:1.0, agreeing with theoretical prediction.
authors.affiliation: School of Molecular Bioscience, Kolling Institute, University of Sydney, Sydney, Australia.
authors.forename: Max
authors.initials: M
authors.lastname: Puckeridge
authors.forename: Bogdan E
authors.initials: BE
authors.lastname: Chapman
authors.forename: Arthur D
authors.initials: AD
authors.lastname: Conigrave
authors.forename: Stuart M
authors.initials: SM
authors.lastname: Grieve
authors.forename: Gemma A
authors.initials: GA
authors.lastname: Figtree
authors.forename: Philip W
authors.initials: PW
authors.lastname: Kuchel
mesh_terms: D001499:Bayes Theorem; D002247:Carbon Isotopes; D004912:Erythrocytes / Q000378:metabolism*; D005947:Glucose / Q000378:metabolism*; D006801:Humans; D017136:Ion Transport; D007700:Kinetics; D009682:Magnetic Resonance Spectroscopy; D008954:Models, Biological; D008985:Monensin / Q000494:pharmacology; D010042:Ouabain / Q000494:pharmacology; D012964:Sodium / Q000378:metabolism*; D061210:Sodium Ionophores / Q000494:pharmacology; D012975:Sodium Isotopes; D000254:Sodium-Potassium-Exchanging ATPase / Q000037:antagonists & inhibitors / Q000378:metabolism
chemical_list: D002247:Carbon Isotopes; D061210:Sodium Ionophores; D012975:Sodium Isotopes; D010042:Ouabain; D008985:Monensin; D012964:Sodium; D000254:Sodium-Potassium-Exchanging ATPase; D005947:Glucose