title: Insulin action on cardiac glucose transport. Studies on the role of the sodium pump.
abstract: Isolated muscle cells from adult rat heart have been used to study the relationship between myocardial glucose transport and the activity of the Na+, K+ pump. 86Rb+ uptake by cardiac cells was found to be linear up to 2 min, with a steady state reached by 40-60 min, and was used to monitor the activity of the sodium pump. Both the ouabain-sensitive and ouabain-insensitive 86Rb+ uptake by cardiac cells were found to be unaffected by insulin treatment under conditions in which a significant stimulation of 3-O-methylglucose transport occurred. 86Rb+ uptake was markedly reduced by the presence of calcium or magnesium or both, but remained unresponsive toward insulin treatment. Inhibition of the sodium-pump activity by ouabain and a concomitant shift in the intracellular Na+/K+ ratio did not affect basal or insulin-stimulated rates of 3-O-methylglucose transport in cardiac myocytes. The data argue against a functional relationship between the myocardial Na+, K+ pump and the glucose-transport system.
authors.forename: J
authors.initials: J
authors.lastname: Eckel
authors.forename: H
authors.initials: H
authors.lastname: Reinauer
mesh_terms: D019325:3-O-Methylglucose; D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D001693:Biological Transport, Active / Q000187:drug effects; D001786:Blood Glucose / Q000378:metabolism*; D007328:Insulin / Q000494:pharmacology*; D007473:Ion Channels / Q000187:drug effects*; D008757:Methylglucosides / Q000378:metabolism; D009206:Myocardium / Q000378:metabolism*; D010042:Ouabain / Q000494:pharmacology; D011188:Potassium / Q000378:metabolism; D051381:Rats; D012413:Rubidium / Q000378:metabolism; D012964:Sodium / Q000378:metabolism*
chemical_list: D001786:Blood Glucose; D007328:Insulin; D007473:Ion Channels; D008757:Methylglucosides; D019325:3-O-Methylglucose; D010042:Ouabain; D000255:Adenosine Triphosphate; D012964:Sodium; D012413:Rubidium; D011188:Potassium