EFFECTS OF 2,4 DINITROPHENOL ON PROXIMAL TUBULAR SODIUM REABSORPTION AND PERMEABILITY TO NONELECTROLYTES IN THE RAT KIDNEY
ARMY AEROMEDICAL RESEARCH LAB FORT RUCKER AL
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A series of 19 experiments were performed to study the effects of 2,4 dinitrophenol 2,4 DNP, an uncoupler of oxidative phosphorylation, on the capacity of the proximal tubule of the rat kidney to reabsorb isotonic sodium chloride and to limit passive permeation of nonelectrolytes. The technique utilized was sequential photomicrography of split oil droplet microperfusions of surface proximal convolutions. The perfusion fluids were isotonic solutions of saline, mannitol, sucrose and raffinose. The addition of 2,4 DNP had no effect on isotonic saline absorptive rate. However it increased the rate of reabsorption of the nonelectrolytes. The results suggest an intimate linkage in the proximal convolution of sodium transport directly to the electron transport system since 2,4 DNP prevents oxidative phosphorylation without inhibiting electron transport. In contrast permeability of this tubular segment to nonelectrolytes is enhanced by 2,4 DNP. At least two mechanistic and two functional explanations are possible for this effect. These are discussed and their implications considered.
- Anatomy and Physiology