Ouabain-sensitive insulin stimulation of ion and glucose transport in rat ventricular slices.
This study was designed to determine whether ouabain could inhibit insulin-stimulated ion and/or glucose transport in rat ventricular slices. In the slices which were obtained by tearing with forceps from the inside surface of the ventricle, insulin (0.1-100 ng/ml, 20-min treatment) stimulated ATP hydrolysis (nmol inorganic phosphate/mg tissue/20 min) and 86Rb uptake (nmol Rb/mg tissue/8 min) in a concentration-dependent fashion by up to about 25%, compared with control experiment. About 10-fold higher concentrations of insulin stimulated glucose-[14C] uptake by the slices (nmol glucose/mg tissue/30 min). Both the stimulant effects of insulin on ion and glucose transport were inhibited by ouabain (0.1-1 mM, 20-min treatment) in a similar concentration-response relationship. It thus never appears that two or more independent transmembrane signals would be generated simultaneously in response to the insulin-receptor interaction to operate ion and glucose transport systems in rat cardiac muscle. In addition, rat ventricular slices were shown to provide a sensitive tool for the evaluation of insulin effects on ion transport systems in the muscle.
D000251:Adenosine Triphosphatases / Q000032:analysis; D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D005947:Glucose / Q000378:metabolism*; D066298:In Vitro Techniques; D007328:Insulin / Q000494:pharmacology*; D008297:Male; D009206:Myocardium / Q000378:metabolism*; D010042:Ouabain / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D012413:Rubidium / Q000378:metabolism
D007328:Insulin; D010042:Ouabain; D000251:Adenosine Triphosphatases; D005947:Glucose; D012413:Rubidium