Effect ofN-methyl-N′-Nitro-N-nitrosoguanidine on amino acid incorporation into mucosal protein of rat stomach

✍ Scribed by Bagewadikar, R. S. ;Bhattacharya, R. K.

• Publisher: John Wiley and Sons
• Year: 1992
• Tongue: English
• Weight: 497 KB
• Volume: 7
• Category: Article
• ISSN: 0887-2082
• DOI: 10.1002/jbt.2570070105

✦ Synopsis

Administration of the carcinogenic N-nitroso compound, N-methy1-AT-nitro-Nnitrosoguanidine in drinking water (0.5 mg/mL) to male Wistar rats for 1 week caused impairment of in vivo and in vitro incorporation of [Wlleucine into stomach mucosal protein. This impairment gradually returned to normal after 4 weeks. Uptake of IWIleucine into mucosal protein was significantly inhibited after in vitro treatment of stomach mucosa wi& the carcinogen. Addition of the N-nitroso compound in a cell-free system using postmitochondrial supernatant prepared from stomach mucosa also showed inhibition of amino acid incorporation. Using a more defined system consisting of purified polyribosome from stomach mucosa and pH 5 enzyme fraction derived from liver it was further demonstrated that the carcinogen purturbed protein synthesizing ability of polyribosome, under both in vivo and in vitro treatment conditions. In these respects this carcinogen has similar action on the target tissue of stomach as in the liver, although the in vivo effect may be related more to toxicity than carcinogenicity.