In Vitro Induction of Ornithine Decarboxylase in Urinary Bladder Carcinoma Cells¹

The induction of ornithine decarboxylase by normal rat urine in bladder cancer cell cultures was tested in view of recent observations that urine acts as a tumor promoter. Addition of urine up to 15% in final concentration to culture medium resulted in a 10-fold increase in ornithine decarboxylase activity over the control. The stimulatory factor(s) contained in urine appears heat stable and may be multiple. 12-O-Tetradecanoylphorbol-13-acetate, a potent promoter in mouse skin carcinogenesis, induced a 39-fold increase in ornithine decarboxylase activity, the best response among the various substances tested. This suggests that it may act as a promoter of bladder cancer.