enng and Body-Weight

The effects of tamoxifen (TAM) on uterine carcinogenesis were investigated in female Donryu rats. The effects were initiated by a single intrauterine treatment with N-ethyl-N'-nitro-N-nitrosoguanidine (ENNG) at a dose of 20 mg/kg body weight via the vagina at 10 weeks of age. TAM tubes (cholesterol tubes containing 50% TAM) were implanted into the backs of the rats for 13 months (full TAM group) or for the second-half of this period (half TAM group). In the control group treated with ENNG alone, various proliferative lesions were induced in the uterine endometrium and the incidence of endometrial adenocarcinomas was about 30%. In contrast, the uteri in both TAM-treated groups showed severe atrophy and the incidences of uterine proliferative lesions were limited to a few endometrial hyperplasias in the half TAM group. Most of the vaginas in both TAM-treated groups showed mucification, while cornification was common in the vaginal epithelium of controls. The ovaries demonstrated similar atrophy with cystic follicles and no corpora lutea in all groups. Other estrogen responsive endocrine organs, such as the pituitaries and adrenals, were small in the TAM-treated groups. Serum estrogen levels in the TAM-treated groups were lower than in the control group but progesterone levels did not differ. These results indicated that TAM acts as an anti-estrogen on the adult rat uterus, inhibiting the development of endometrial adenocarcinomas initiated by ENNG.

Topics: Adrenal Glands; Animals; Anticarcinogenic Agents; Body Weight; Carcinogenicity Tests; Endometrial Neoplasms; Estradiol; Female; Gonads; Liver; Methylnitronitrosoguanidine; Organ Size; Pituitary Gland; Progesterone; Rats; Rats, Inbred Strains; Tamoxifen; Uterus

Fucoxanthin was shown to inhibit chemical carcinogenesis. Fucoxanthin is a natural carotenoid prepared from brown algae which is an ingredient used daily in Japanese food. In this study, all mice were given 0.01% N-ethyl-N'-nitro-N-nitrosoguanidine in their drinking water for 4 weeks. This was followed by 0.005% fucoxanthin in dimethylsulfoxide or the vehicle alone in the drinking water. In the 16-week fucoxanthin-treated group both the percentage of tumor-bearing mice and the average number of tumors per mouse were significantly lower than those of the control group. The results indicate that fucoxanthin inhibited duodenal carcinogenesis induced by N-ethyl-N'-nitro-N-nitrosoguanidine in mice.

Topics: Animals; Body Weight; Carcinogens; Carotenoids; Duodenal Neoplasms; Methylnitronitrosoguanidine; Mice; Xanthophylls

We examined whether orally administered RBS (rice bran saccharide), prepared from rice bran by hot water extraction, increases immunocompetence, inhibits gastrointestinal carcinogenesis with N-ethyl-N'-nitro-N-nitrosoguanidine (ENNG) or shows an antitumor effect. After the administration of RBS, phytohemagglutinin (PHA)- and pokeweed mitogen (PWM)-stimulated blastogenesis of lymphocytes derived from the mesenteric lymph nodes and peripheral blood was enhanced, and the helper/suppressor T-cell ratio was elevated, and migration activity of peritoneal macrophages was also increased in rats treated continuously with ENNG. ENNG-induced gastrointestinal carcinomas were observed in 43% of those administered RBS (ENNG-RBS) as compared with 88% in the control (ENNG) and 94% in the prednisolone (PRD) group (ENNG-PRD). The 12-month survival rate of rats bearing gastrointestinal cancer was 58% in the ENNG-RBS group as compared with 25% in the ENNG group and 15% in the ENNG-PRD group. RBS prevented the reduction in immunocompetence in the course of carcinogenesis, suppressed carcinogenesis, and prolonged the survival of rats with gastrointestinal cancer. Antitumor activities of RBS are thought to be a kind of host mediated action. The growth inhibition ratio of transplantable ENNG-induced cancer in Wistar rats was 42.1% in the RBS and 51.8% in the 5-FU group. Since little is known about the potent antitumor activity of alpha-glucan, it would be interesting to consider the relationship between the structure and the biological activities of polysaccharides.

Topics: Adjuvants, Immunologic; Administration, Oral; Animals; Antineoplastic Agents; Body Weight; Chemotaxis; Gastrointestinal Neoplasms; Glucans; Immunocompetence; Lymphocyte Activation; Lymphocyte Subsets; Macrophages; Male; Methylnitronitrosoguanidine; Neoplasm Transplantation; Rats; Rats, Inbred Strains

Therapeutic effects and dynamics of UFT were studied using beagles with ENNG-induced gastric cancers. Nine canine subjects confirmed to have gastric cancers by punch biopsy under gastrofiberscopy were divided into 3 group given 5 mg/kg/day of UFT for 101 days, 7.5 mg/kg/day for 67 days and 12 mg/kg/day for 45 days, respectively. Although the extent of macroscopic change revealed by gastrofiberscopy was minor, one of the dogs in the third group did show a Grade II b effect according to the criteria of Histopathological Effects on Cancer Tissues by Chemotherapy proposed by Oboshi and Shimozato. Animals were sacrificed by bleeding 4 hours after the last administration of anticancer agent and concentration of 5-FU and tegafur in the serum and each organ were determined. It was recognized that the concentration of anticancer agent in gastric cancer tissue was higher than that in neighboring normal gastric tissue.

Topics: Animals; Antineoplastic Combined Chemotherapy Protocols; Body Weight; Dogs; Male; Methylnitronitrosoguanidine; Stomach Neoplasms; Tegafur; Tissue Distribution; Uracil

Effects of NaCl, Tween 60 and N-ethyl-N'-nitro-N-nitroso-guanidine (ENNG) on gastric carcinogenesis were investigated in male Wistar rats. Animals received a single dose of N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) at 250 mg/kg body weight by gastric tube followed one week later by either 10% NaCl in their diet, twice-weekly applications of 1 ml of saturated NaCl solution by gastric tube, 1.0% Tween 60 in their drinking water or 0.0005% ENNG in their drinking water. One group of rats were given MNNG 24 h after a single application of 1 ml of saturated NaCl solution to investigate the effect of NaCl on initiation. A single dose of MNNG to rats resulted in development of multiple epithelial tumors in the forestomach and no epithelial tumors in the glandular stomach after 52 weeks. There were no differences in tumor incidences of the forestomach and glandular stomach between experimental groups which were given a subsequent treatment with NaCl or Tween 60 and the control group with MNNG alone. ENNG significantly enhanced the tumor induction in the glandular stomach, while ENNG alone did not induce any tumors in the stomach. The NaCl treatment prior to MNNG administration also increased tumor development in the glandular stomach but not in the forestomach.

Topics: Animals; Body Weight; Male; Methylnitronitrosoguanidine; Neoplasms, Experimental; Polysorbates; Rats; Rats, Inbred Strains; Sodium Chloride; Stomach Neoplasms