Effect of prolonged administration of gastrin on experimental carcinogenesis in rat colon induced by intrarectal instillation of N-methyl-N'-nitro-N-nitrosoguanidine.

The effect of tetragastrin on the incidence and histology of colonic tumors induced by intrarectal instillation of N-methyl-N'-nitro-N-nitrosoguanidine was investigated in Wistar rats. Prolonged administration of tetragastrin in depot form during and after treatment with N-methyl-N'-nitro-N-nitrosoguanidine resulted in a significant reduction in the incidence of colonic tumors in Experimental Week 35. Histological examinations showed that, unlike the well-differentiated adenocarcinomas with a typical glandular pattern in control groups, the adenocarcinomas that developed in rats treated with tetragastrin had high mucin-producing activity.