7,12-Dimethylbenz[a]anthracene

About: 7,12-Dimethylbenz[a]anthracene is a research topic. Over the lifetime, 1717 publications have been published within this topic receiving 40892 citations.

Carcinogenic effects of intragastric 3-methylcholanthrene and 7,12-dimethylbenz[a]anthracene in Wistar and Sprague-Dawley rats.

Abstract: In 2 experiments involving 384 rats of the Wistar (W) and Sprague-Dawley (SD) strains, the carcinogenic effects of repeated intragastric instillations of 3-methylcholanthrene (MCA) were compared with those of single intragastric doses of 7,12-dimethylbenz[a]anthracene (DMBA). Mammary carcinomas appeared in a higher proportion and earlier in SD than in W rats exposed to either carcinogen (during 36 weeks, 90 vs. 50% with MCA in SD and W rats, at an average of 12 and 15 weeks, respectively, and 80 vs. 64% with DMBA in SD and W rats, at an average of 16 and 22 weeks, respectively). Fibroadenomas of the breast were seen in 20 percent of SD rats by 36 weeks. In W rats observed for 1 year following DMBA administration, Fibroadenomas occurred in 64 percent and adenosis in 49 percent, at an average of 45 to 51 weeks, whereas after MCA administration these reactions occurred in less than 10 percent. Intraluminal secretion indicative of lactation was noted in approximately 20 percent of fibroadenomas and adenoses. Nine W rats developed lymphoma, 5 following DMBA and 4 following MCA administration. Uterine papillary formations were observed in 1 W and 2 SD rats, and uterine carcinomas in 2 SD rats; 3 animals had received DMBA and 2, MCA.

Studies of the absorption and enterohepatic circulation of 7,12-dimethylbenz [a] anthracene in the rat

Abstract: This study was undertaken to examine intraluminal factors which might alter the bioavailability of an orally ingested hydrocarbon carcinogen, 7,12-dimethylbenz[a]anthracene, and to assess the extent of its enterohepatic circulation. Rats with biliary and duodenal fistulae were administered radiolabelled hydrocarbon dissolved in olive oil, safflower oil, or medium-chain triglyceride only or with exogenous bile. Subsequent biliary excretion and plasma levels of radiolabel were monitored. Luminal bile significantly enhanced biliary recovery of radiolabel following instillation in both long-chain triglyceride vehicles, but did not affect the recovery from the medium-chain oil. In the presence of luminal bile, plasma levels and biliary recovery of radiolabel using the medium-chain triglyceride were significantly less than with either long-chain triglyceride. Following intraduodenal infusions of the radiolabelled biliary products of the carcinogen, 33% of the administered radiolabel was subsequently reexcreted ...

Dose-Dependent Protection by Tomato Against 7,12-Dimethylbenz[a]anthracene-Induced Genotoxicity and Oxidative Stress in Mice

Abstract: This study was designed to investigate the protective role of pretreatment with graded doses of freshly prepared tomato paste against 7,12-dimethylbenz[a]anthracene (DMBA)-induced genetic damage and oxidative stress in male Swiss mice. The incidence of bone marrow micronuclei and the extent of hepatic lipid peroxidation and the antioxidants glutathione, glutathione peroxidase, and glutathione S-transferase were monitored. Three different concentrations (0.5, 1, and 2 g/kg body weight) of tomato paste were tested for their anticlastogenic effects against DMBA (35 mg/kg body weight). Increased frequency of micronuclei and enhanced lipid peroxidation accompanied by compromised antioxidant defenses were observed in DMBA-treated animals. Pretreatment with all three doses of tomato paste significantly reduced the frequencies of DMBA-induced micronuclei and oxidative stress. These findings demonstrate that administration of tomato paste protects against the clastogenic effects of DMBA by decreasing lipid peroxidation and enhancing the antioxidant status.

Reduction in 7,12-Dimethylbenz[a]anthracene-Induced Hepatic Cytochrome-P450 1A1 Expression Following Soy Consumption in Female Rats Is Mediated by Degradation of the Aryl Hydrocarbon Receptor

Abstract: Consumption of a soy diet has been found to reduce cancer incidence in animals and is associated with reduced cancer risk in humans. In this study, the effect of consuming soy protein isolate (SPI) on the aryl hydrocarbon receptor (AhR)-mediated signaling pathway was investigated. Female Sprague-Dawley rats were fed AIN-93G diets with (+) or without (-) SPI-bound phytochemicals or casein (CAS) protein and gavaged orally with 7,12-dimethylbenz[a]anthracene (DM BA) or sesame oil. We found reduced (P 20 d. Experiments in which SPI + -fed rats were weaned to CAS diets demonstrated that AhR reduction by SPI + is not imprinted metabolically. To determine the molecular mechanisms of SPI + -mediated AhR reduction, an ex vivo model was developed using FGC-4 cells treated with serum from CAS- or SPI + -fed rats. SPI + serum treatment of FGC-4 cells reduced AhR expression and DMBA-induced CYP1A1 expression (P < 0.05). The reduction in AhR expression was in part due to the shorter half-life of AhR protein. Our findings suggest that the cancer preventive effect of soy-based diets is mediated in part by reduction in AhR protein level posttranslationally, which reduces procarcinogen-induced CYP1A1 induction and metabolic activation.