Diamine oxidase activity in rat brain carcinogenesis and in gliomas.

In the early stages of brain carcinogenesis induced by transplacental administration of N-ethyl-N-nitrosourea to BD IX rats, a constant increase in the activity of cerebral diamine oxidase, the rate-limiting enzyme in terminal catabolism of polyamines, was observed. Gliomas, which developed between the fifth and eight month of extrauterine life, showed an 8-fold increase in enzyme activity compared with normal brain from rats of the same age. Concomitantly, an 11-fold enhancement in putrescine, a physiological substrate of diamine oxidase, was also found. Such findings indicate that an increase in oxidative putrescine catabolism via diamine oxidase takes place in transformed cells and in gliomas and is probably linked to an activation of polyamine synthesis and turnover.