ATTENUATING EFFECT OF THE MONOAMINE-OXIDASE INHIBITOR FURAZOLIDONE ON THE ANTI-CARCINOGENETIC EFFECT OF CYSTEAMINE ON GASTRIC CARCINOGENESIS INDUCED BY N-METHYL-N'-NITRO-N-NITROSOGUANIDINE IN WISTAR RATS

The effect of furazolidone on inhibition by cysteamine of gastric carcinogenesis induced by N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) was investigated in inbred Wistar rats. After oral treatment with MNNG for 25 weeks, rats received cysteamine, furazolidone, or both compounds. In week 52, rats treated with cysteamine had a significantly decreased incidence of gastric cancers. Concomitant treatment with furazolidone significantly attenuated the inhibitory effect of cysteamine on gastric carcinogenesis. Administration of furazolidone alone significantly increased the number, but not the incidence, of gastric cancers. The norepinephrine concentration of the antral portion of the gastric wall and the labelling index of the antral mucosa were significantly reduced in rats treated with cysteamine, and significantly higher in rats treated with both compounds than in those treated with cysteamine alone. These findings indicate that the cysteamine-induced inhibition of gastric carcinogenesis is mediated by catecholamines.