Effects of urinary transferrin and ornithine decarboxylase-inducing fraction on rat bladder carcinogenesis

Using heterotopically transplanted rat urinary bladder (HTB) system, we previously have shown that contact with urine enhanced bladder carcinogenesis initiated by carcinogen. In order to screen urine for promoter substances, several short term in vitro assays were developed and their results were correlated with the in vivo assay results. Chromatographically separated urine fractions were examined for the inability to induce ornithine decarboxylase (ODC), to enhance incorporation of [3H]thymidine in a bladder carcinoma cell line (804G) and to form colonies in soft agar by NRK-49F. Data from the ODC assay and soft agar colony formation correlated well with the results derived from chronic animal studies. Thus then two assays appear useful in further screening urine for promoter substance. Data furthermore indicate that ODC-inducing urine component(s) may play a primary role in the steps following initiation whereas transferrin, a mitogenic urine component, may play a secondary role.