SODIUM EXTRUSION AND POTASSIUM UPTAKE IN GUINEA PIG KIDNEY CORTEX SLICES.
Slices from the cortex corticis of the guinea pig kidney were immersed in a chilled solution without K and then reimmersed in warmer solutions. The Na and K concentrations and the membrane potential V(m) were then studied as a function of the Na and K concentrations of the reimmersion fluid. It was found that Na is extruded from the cells against a large electrochemical potential gradient. Q(10) for net Na outflux was approximately 2.5. At bath K concentrations larger than 8 mM the behavior of K was largely passive. At the outset of reimmersion (V(m) > E(K)) K influx seemed secondary to Na extrusion. Na extrusion would promote K entrance, being limited and requiring the presence of K in the bathing fluid. At bath K concentrations below 8 mM, K influx was up an electrochemical potential gradient. Thus a parallel active K uptake is apparent. Q(10) for net K influx was approximately 2.0. Dinitrophenol inhibited net Na outflux and net K influx, Q(10) became <1.1 for both fluxes. The ratio between these fluxes varied. Thus at the outset of reimmersion the net Na outflux to net K influx ratio was >1. After 8 minutes it was <1.
D000818:Animals; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D004140:Dinitrophenols; D006168:Guinea Pigs; D007477:Ions; D007668:Kidney; D007672:Kidney Cortex; D008564:Membrane Potentials; D008660:Metabolism; D011188:Potassium; D012106:Research; D012964:Sodium
D004140:Dinitrophenols; D007477:Ions; D012964:Sodium; D011188:Potassium
CHEMISTRY, PHYSICAL; DINITROPHENOLS; EXPERIMENTAL LAB STUDY; GUINEA PIGS; KIDNEY; METABOLISM; POTASSIUM; SODIUM