Effect of D-glucose on oxygen consumption of renal proximal tubules of the Triturus.
Effect of exogenous D-glucose on oxygen consumption (QO2) was investigated in the proximal tubules of the Triturus kidney. In the proximal tubule, which was perfused and incubated with a solution containing Na+, QO2 was increased dependently of the concentration of added glucose. By removal of Na+ from the perfusate and incubation solutions, QO2 kept the level even by increasing adding glucose. The glucose dependence of Qo2 in the proximal tubule showed the saturable manner of a Michaelis-Menten type and gave a half saturation concentration of 1.3 mM. When phlorizin (1 X 10(-3) M) or ouabain (1 X 10(-3) M) was added to the perfusate and incubation solutions, the glucose dependency of QO2 was abolished, even in the Na+-containing solution. When alpha-methyl-D-glucoside (alpha-MG) was used instead of D-glucose, the QO2 of the proximal tubule showed a dependency on the concentration of alpha-MG. On the other hand, when D-mannitol was used instead of D-glucose, the QO2 was independent on the concentration of D-mannitol. The increase in QO2 of the proximal tubule by exogenous D-glucose could be explained by the stimulation of the Na+ pump, which is the consequence of enhanced Na+ entry through Na+/D-glucose cotransport across the luminal membrane.
D000818:Animals; D005947:Glucose / Q000494:pharmacology*; D007473:Ion Channels / Q000187:drug effects / Q000378:metabolism; D007687:Kidney Tubules, Proximal / Q000378:metabolism*; D007700:Kinetics; D008353:Mannitol / Q000494:pharmacology; D008757:Methylglucosides / Q000494:pharmacology; D010042:Ouabain / Q000494:pharmacology; D010101:Oxygen Consumption / Q000187:drug effects*; D010695:Phlorhizin / Q000494:pharmacology; D012964:Sodium / Q000378:metabolism / Q000494:pharmacology; D014319:Triturus / Q000378:metabolism*
D007473:Ion Channels; D008757:Methylglucosides; D008353:Mannitol; C027020:methylglucoside; D010042:Ouabain; D012964:Sodium; D010695:Phlorhizin; D005947:Glucose