Abstract

The factors influencing the rate of run out of PAH from dog renal slices have been studied. Acetate and lactate can decrease the rate of run out of PAH. Succinate and α-ketoglutarate only increase the rate of run out of PAH. Octanoate on the other hand increased in low and decreased run out rate of PAH in high concentrations. Cyanide, azide, iodoacetate and mercury bichloride increased run out rate in all concentrations studied. 2,4-Dinitrophenol produced a biphasic effect increasing in low and decreasing the rate of run out of PAH at higher concentrations. In a similar manner iodopyracet, probenecid and bromcresol green increased in low and decreased PAH run out in high concentrations. It is proposed that in low concentrations all these substances having biphasic effects act mainly on the intracellular PAH concentrating mechanism. The effects of higher concentrations are most probably due to competitive effects on the membrane transport process.