sodium-nitrite and Adenoma

The modifying effects of concurrent administration of fish meal and sodium nitrite on the development of renal tumors after initiation with N-ethyl-N-hydroxyethylnitrosamine (EHEN) were investigated. A total of 120 male 6-week-old Wistar rats were divided into six groups. Groups 1-3 (30 animals each) were given 1000 ppm EHEN in their drinking water for 3 weeks as an initiation treatment for renal cancer induction and thereafter fed respective diets containing 64, 32, and 8% (original concentration in the basal diet) fish meal, and simultaneously given 0.12% sodium nitrite in the drinking water for 33 weeks. Groups 4-6 (ten animals each) were similarly treated without the prior application of EHEN. At the end of the 37th experimental week, all surviving animals were autopsied and examined histopathologically for the existence of renal proliferative lesions. The incidences of dysplastic lesions, adenomas or adenocarcinomas of the kidney were not significantly different among groups 1-3. No renal proliferative lesions were found in groups 4-6. Chronic nephropathy was slightly but significantly enhanced in the 64 and 32% fish meal-treated groups as compared with group 3. Our results suggest that concurrent administration of fish meal and sodium nitrite does not affect the post-initiation phase of EHEN-induced renal carcinogenesis in the rat.

Topics: Adenocarcinoma; Adenoma; Adrenal Glands; Animals; Body Weight; Cocarcinogenesis; Diet; Diethylnitrosamine; Fish Products; Kidney; Kidney Neoplasms; Liver; Male; Organ Size; Proliferating Cell Nuclear Antigen; Rats; Rats, Wistar; Sodium Nitrite; Time Factors

The effects of sodium nitrite (NaNO2) and catechol or 3-methoxycatechol in combination were examined in male F344 rats. Animals were treated with 0.3% NaNO2 in the drinking water and 0.8% catechol or 2% 3-methoxycatechol in powdered diet for 24 weeks. While catechol or 3-methoxycatechol alone induced low incidences of mild or moderate hyperplasia, simultaneous administration of NaNO2 markedly enhanced the degree of hyperplasia and papilloma formation. In contrast, induction of submucosal hyperplasia and adenomas in the glandular epithelium was reduced. Thus, the results indicate that NaNO2 can modulate the metabolism of antioxidants, so that, possibly via production of new active moieties, targeting of forestomach epithelium is enhanced.

Topics: Adenoma; Animals; Antioxidants; Body Weight; Catechols; Drug Synergism; Epithelium; Feeding Behavior; Hyperplasia; Male; Neoplasms, Experimental; Organ Size; Rats; Rats, Inbred F344; Sodium Nitrite; Stomach; Stomach Diseases; Stomach Neoplasms

Sodium nitrate was given to male noninbred Wistar rats at levels of 800 ppm and 1,600 ppm in a pellet diet for 646 experimental days. The first tum or was found on day 441 in the liver of a rat given a diet containing 800 ppm sodium nitrite. On day 646, liver tumors were found in 1 of 22 rats (4.5%) on an 800-ppm sodium nitrite diet and in 5 of 19 rats (26.3%) on a 1,600-ppm sodium nitrite diet. The incidence of liver tumors in the rats fed 1,600 ppm sodium nitrite was significantly different from that in controls as judged by the t-test (P < 0.05). A hepatocellular carcinoma and a hemangioendothelial sarcoma of the liver were found on day 646 in 2 rats fed 1,600 ppm sodium nitrite. One mammary tumor but no liver tumors were found in the 19 control rats. The concentration of sodium nitrite decreased after preparation of the pellet diet, but it was still at least 70% of the initial amount when the pellets were given to the rats. Volatile N-nitroso compounds, especially dimehylnitrosamine, at ppm levels were detected in the pellet diet with a gas chromatography-thermal energy analyzer.

Topics: Adenoma; Animals; Carcinogens; Carcinoma; Diet; Dose-Response Relationship, Drug; Hemangiosarcoma; Liver Neoplasms; Male; Neoplasms, Experimental; Nitrites; Nitroso Compounds; Rats; Sodium Nitrite; Time Factors