Intestinal absorption of oxalate by xylitol-treated rats and mice

The absorption of 14C-labelled oxalic acid was studied in Wistar rats, CD-1 mice and NMRI mice. Oxalic acid in solution was given to the animals by gavage either with water alone or with 0.625 g/kg b.w. of xylitol. Both xylitol-adapted animals and animals not previously exposed to xylitol were used. Adaptation to xylitol diets enhanced the absorption and urinary excretion of the label (oxalic acid) in both strains of mice but not in rats. Earlier studies have indicated a high incidence of bladder calculi in mice but not in rats fed high amounts of xylitol. The results of the present study offer one likely explanation for the increased formation of bladder calculi as a result of oversaturation of urine with oxalate.