The Effect of Temperature on the Uptake of Radiosulfate by Rat Renal Tissue from Radiosulfate-Containing Solutions in Vitro

Kidney cortex slices incubated in vitro at 0°C. accumulate radiosulfate from the incubation medium. This process differs from the previously described uptake of radiosulfate by renal tissue incubated at 38°C., for instance, in the lesser sensitivity of the uptake at 0°C. to differential effects of Na⁺ as compared with K⁺ ions, and of sucrose as compared with glucose. Phlorizin inhibits radiosulfate accumulation at 0°C., whereas it enhances the uptake at 38°C. Effects of the cations K⁺ and Na⁺ and of phlorizin at temperatures intermediate between 0° and 38°C. have been studied. Parallels have been noted between the accumulative processes for radiosulfate of kidney slices maintained at 0°C. and of mitochondria isolated from rat liver and kidney cortex. These similarities may be attributed to an important role of radiosulfate uptake by mitochondria in slice accumulation of radiosulfate in the cold.