Heterogeneous response of isolated adult rat heart cells to insulin.
3-O-Methylglucose uptake by Ca2+-resistant adult rat heart cells in suspension was measured, free of artifactual inhibitor-insensitive uptake, and with an accuracy of +/- 1.9% pellet water. (Ca2+-resistant cells are cells which retain their original rod-shaped morphology in the presence of physiological levels of Ca2+.) High levels of insulin (10(-6) M) stimulated the rate of 3-O-methylglucose uptake approximately 10-fold. In the presence of low levels of insulin (3 X 10(-11) M, 10(-10) M) uptake was biphasic; it could not be described by a single exponential function within experimental error, but required the sum of two exponentials. Deviation from a single exponential function was not so great with high levels of insulin (10(-6) M) or no insulin. Cell sugar uptake was also investigated using autoradiography of cells which had accumulated [2-14C]deoxyglucose under similar conditions. This showed considerable heterogeneity of 2-deoxyglucose uptake by cells treated with low levels of insulin, but significantly less heterogeneity of 2-deoxyglucose uptake by cells treated with high levels of insulin. It is concluded that the deviation of 3-O-methylglucose uptake from a single exponential observed at low insulin levels can be accounted for in terms of a heterogeneous response of cells to insulin.
D019325:3-O-Methylglucose; D000818:Animals; D001345:Autoradiography; D001693:Biological Transport, Active / Q000187:drug effects; D002118:Calcium / Q000494:pharmacology; D002250:Carbon Radioisotopes; D003571:Cytochalasin B / Q000494:pharmacology; D006321:Heart / Q000187:drug effects*; D066298:In Vitro Techniques; D007328:Insulin / Q000494:pharmacology*; D007700:Kinetics; D008757:Methylglucosides / Q000378:metabolism*; D008759:Methylglycosides / Q000378:metabolism*; D009206:Myocardium / Q000378:metabolism*; D051381:Rats
D002250:Carbon Radioisotopes; D007328:Insulin; D008757:Methylglucosides; D008759:Methylglycosides; D019325:3-O-Methylglucose; D003571:Cytochalasin B; D002118:Calcium