Spermidine/Spermine N‐Acetyltransferase, a New Biochemical Marker for Epithelial Proliferation in Rat Bladder

We examined the activity of spermidine/spermine N(1)‐acetyltransferase (SAT), a rate‐limiting enzyme of the biodegradation of polyamines, in N‐butyl‐N‐(4–hydroxybutyI)nitrosamine‐induced transitional cell carcinoma (TCC) and melamine‐induced papillomatosis of rat bladder, and compared the activity to that of ornithine decarboxylase (ODC). Both activities were higher in both lesions than in control rats. The difference between SAT and ODC activities in cancerous tissue and papillomatosis was not significant. Cells stained for proliferating cell nuclear antigen (PCNA) were abundant in papillomatosis. TCC had areas with much PCNA. The results indicated that an elevation of SAT activity occurs in both reversible and irreversible proliferation of bladder epithelium and could be important in bladder carcinogenesis.