Fig. 5
Adaptation to aglycemic growth conditions enhanced metabolic response to plasmalemmal sodium potential uncoupling. To assess the response to an increased energy demand, the cells were exposed to the sodium ionophore monensin, which induces increased ATP utilization through Na+/K+ ATPase pumps that is sensitive to the Na+/K+ ATPase inhibitor ouabain. a Schematic diagram of monensin action. b Example trace of respiration (JO2) and proton efflux (JH+) rates in response to monensin, followed by inhibition of the Na+/K+ ATPase inhibitor ouabain. c Glucose-supported stimulated energy demand (calculated by subtracting the basal rate from the ouabain-corrected monensin rate for both JATPOxPhos and JATPGlyc) represents the rate increase that is attributable to the monensin. d Pyruvate-supported stimulated energy demand. e Glutamine-supported stimulated energy demand. f Glucose-supported total stimulated ATP production rates (sum of OxPhos and glycolysis). g Pyruvate-supported total stimulated ATP production rates. h Glutamine-supported total stimulated ATP production rates. N = 8/treatment/group. Data are mean ± SEM. Means were compared using Student’s t test. *p < 0.05. ns = not significant