Bladder calculi in rats treated with nitrosomethylurea and fed artificial sweeteners.

Female Wistar rats treated once with nitrosomethylurea (NMU) by urinary bladder instillation were given saccharin, cyclamate or calcium carbonate in the diet for life. X-ray examinations were performed every three weeks to detect early formations of urinary bladder calculi, while an intravenous pyelogram and cystography served as a method for detection of neoplastic alterations. No statistical correlation could be established between the occurrence of urinary bladder stones and neoplasma in the various groups.