Enhancement by propranolol of the inhibitory effect of tetragastrin on gastric carcinogenesis induced by N-methyl-N'-nitro-N-nitrosoguanidine in Wistar rats
Tatsuta, M.; Iishi, H.; Yamamura, H.; Taniguchi, H.
Cancer Research 47(1): 111-114
1987
ISSN/ISBN: 0008-5472 PMID: 3791197 Document Number: 302586
The effects of combined administration of propranolol and tetragastrin on gastric acid secretion and the incidence and histological types of gastric adenocarcinomas induced by N-methyl-N'-nitro-N-nitrosoguanidine were investigated in inbred Wistar rats. Prolonged administration of tetragastrin, 1 but not 0.2 mg/kg body weight in depot form after treatment with N-methyl-N'-nitro-N-nitrosoguanidine significantly reduced the incidence of adenocarcinoma of the glandular stomach. The adenocarcinomas that did develop in rats treated with the higher dose of tetragastrin had high mucin-producing activity and showed little or no typical glandular structure. A combination of propranolol (2 mg/kg) and tetragastrin (1 mg/kg) did not influence the inhibitory effect of gastrin on gastric carcinogenesis. However, concomitant administration of propranolol (2 mg/kg) and tetragastrin (0.2 mg/kg) caused a significant increase in gastric acid secretion and a reduction in the incidence of gastric carcinomas. With this treatment, the incidence of adenocarcinoma was similar to that of treatment with tetragastrin (1 mg/kg). Histological examinations showed that like the cancers in control rats, the adenocarcinomas induced in these rats were all highly differentiated.