Blood polyamine levels after oral ornithine load, a diagnostic marker of hyperproliferative premalignant and malignant stages in a model of colon carcinogenesis

This study was performed to determine whether a single oral dose of ornithi ne (Orn), the substrate of ornithine decarboxylase (ODC), increases blood c oncentrations of polyamines premalignant stage, and whether blood polyamine levels could be used as predictive markers of cancer development. Male Wis tar rats were divided into two groups, control and 1,2-dimethylhydrazine (D MH)-treated rats. DMH (20 mg/kg body weight) was injected intraperitoneally once weekly for 10 weeks. Five, 7, and 10 weeks after the last injection w hen premalignant aberrant crypt foci have developed in the colon, blood lev els of putrescine (PUT), spermidine (SPD), and spermine (SPM) were estimate d before and after an oral load of ORN. The results showed that after a sin gle oral load of Orn, blood PUT, but not SPD and SPM, concentrations were s ignificantly higher in DMH-treated rats compared with control rats, indicat ing enhancement of ODC activity. These results support the view that the in creased blood concentration of PUT after administration of Om may be a usef ul marker to detect hyperproliferative premalignant and malignant stages of cancer development.