Intracellular Accumulation as an Active Process in a Mammalian Renal Transport System in Vitro

Abstract
Studies on thin slices of rabbit renal cortex indicate that substances which accumulate in vitro are concentrated intracellularly without further discernible concentration in the lumen. Movement into cells of the proximal tubules is an active process dependent upon aerobic phosphorylation and subject to competitive inhibition involving p-aminohippurate, phenol red, chlorphenol red and benemid. All experimental indications are that this is the first step in the over-all transfer of these substances by renal tubules in the intact kidney.