Transport of L-ascorbic acid and dehydro-L-ascorbic acid across renal cortical basolateral membrane vesicles

The uptake of L-ascorbic acid and dehydro-L-ascorbic acid into renal cortical basolateral membrane vesicles has been characterized. The uptake systems for both solutes demonstrate saturation kinetics. The presence of structural analogs of L-ascorbic acid and dehydro-L-ascorbic acid results in cis-inhibition and trans-stimulation. Uptake of each substrate is Na+-independent, proceeding to an endpoint of substrate equilibrium across the vesicular membrane. The transport mechanism(s) for L-ascorbic acid and dehydro-L-ascorbic acid appears to be facilitated diffusion.