EVIDENCE FOR ACTIVE TRANSPORT OF CHOLINE IN RAT KIDNEY CORTEX SLICES

Abstract
The oxidation of methyl-14C-choline to betaine in rat kidney cortex slices is inhibited by DNP, by the hemicholinium, HC-3, and by the absence of Na+from the incubation medium. Corresponding inhibitions are not observed in kidney homogenates although appreciable conversion of choline to betaine takes place. The data suggest that choline transport occurs in rat kidney cortex and that it is an ATP- and Na+-dependent process. In Ehrlich ascites tumor cells, phosphocholine is accumulated to an appreciable extent in the cells, but no evidence for a specific choline transport mechanism was obtained.