Distension of the urinary bladder in rats fed saccharin containing diet

The administration of a diet containing 7.5% saccharin ad libitum to rats for 1 month caused an increase in the daily water intake and total urine volume. The greater urine volume was associated with an increase in both the frequency of urination and the average volume per urination. In saccharin-fed rats the total number of urinations per 24 h which exceeded 1.0 ml was increased 3-fold whilst the maximum urination volume detected was almost doubled. These results show that the short-term administration of the high dietary levels used in previous 2-generation cancer bioassays produces functional changes in the urinary bladder, the organ showing an increased incidence of tumours.