FURTHER OBSERVATIONS ON UPTAKE OF S35-LABELLED SULFATE BY RENAL TISSUE IN VITRO

Abstract

Accumulation of S35 by renal cortical tissue incubated in vitro in media containing radiosulfate occurred in the case of 4 mammalian species, although significant uptake was not observed in 3 species of lower vertebrates. In the case of rat renal tissue, S35 accumulation was found to be sensitive to changes in medium pH, osmotic pressure, anionic composition, etc. Studies were made of the effects of various factors known to be related to in vitro accumulative processes for phenol red and PAH, as well as to in vivo sulfate reabsorption in the intact dog. Phlorhizin enhanced S35 uptake. All other substances tested (metabolic intermediates, metabolic inhibitors, competitive inhibitors for PAH transport, ATP, amino acids) lessened S35 accumulation, or were without effect upon it.