title: Gastrin has no promoting effect on chemically induced colonic tumors in Wistar rats.
abstract: The effects of prolonged administration of tetragastrin from the beginning of intrarectal instillation of 1 ml of 0.25% N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) and after MNNG-treatment on the incidence and histology of colonic tumors were compared in inbred Wistar rats. In week 35 prolonged administration of testragastrin in depot form from the beginning of MNNG-treatment resulted in a significant reduction in the incidence of colonic tumors and a significant increase in the incidence of mucinous adenocarcinoma, unlike the well-differentiated adenocarcinoma produced in controls without gastrin. In contrast, prolonged administration of tetragastrin after MNNG-treatment had little or no influence on the incidence, size or histology of colonic tumors. Thus tetragastrin had no promoting effect on colonic tumors.
mesh_terms: D000230:Adenocarcinoma / Q000139:chemically induced; D000818:Animals; D003043:Cocarcinogenesis; D003110:Colonic Neoplasms / Q000139:chemically induced* / Q000473:pathology; D004334:Drug Administration Schedule; D005755:Gastrins / Q000633:toxicity*; D008297:Male; D008769:Methylnitronitrosoguanidine; D009362:Neoplasm Metastasis; D051381:Rats; D011919:Rats, Inbred Strains; D013758:Tetragastrin / Q000008:administration & dosage / Q000633:toxicity*
chemical_list: D005755:Gastrins; D013758:Tetragastrin; D008769:Methylnitronitrosoguanidine