Effects of sodium cyclamate and sodium saccharin on focus induction in explant cultures of rat bladder

The tumour‐promoting activities of sodium cyclamate and sodium saccharin were investigated in an assay based on the induction of epithelial foci exhibiting enhanced growth potential in a rat bladder explant culture system. An initiating, nonfocus‐inducing dose was defined for the carcinogen N‐methyl‐N‐nitrosourea (MNU) to make promotion studies possible, Saccharin induced epithelial foci when added to cultures pretreated with an initiating dose of MNU, and also increased the incidence of foci in cultures treated with transforming doses of MNU. Cyclamate was found to induce a high incidence of foci when added to cultures by itself. When MNU and cyclamate treatments were combined, an additive effect could be detected. These results indicate that both cyclamate and saccharin can contribute to epithelial transformation in this system.

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