The effect of different salts of saccharin on the rat urinary bladder.

Weanling male F344 rats were fed the sodium, potassium, or calcium salt of saccharin or acid saccharin as 5% of the diet by weight for 10 weeks. Sodium saccharin induced significant urinary bladder epithelial proliferation as determined by the labelling index following [3H]thymidine incorporation and by light and scanning electron microscopic evaluation. Potassium saccharin also significantly increased the labelling index but less than the sodium salt. Calcium saccharin and acid saccharin did not significantly increase the labelling index. Similar differences were evident by light and scanning electron microscopy. These differences were not due to differences in the level of saccharin excretion in the urine following feeding of the various salts. Differences in urinary pH and urinary concentration of sodium and calcium were observed between rats fed the various forms of saccharin.