Aryl hydrocarbon hydroxylase in mouse skin epidermis was inducible by topical applications of 1,2,5,6-dibenzanthracene (DBA), 7,12-dimethylbenz[a] anthracene (DMBA), and 5,6benzoflavone. 7,8-Benzoflavone given topically inhibited the enzyme activity; phénobarbitalgiven topically had little or no effect on this enzyme activity. 7,8-Benzoflavone given at the same time as DMBA inhibited the forma...

The hepatoprotective potential of aqueous Azadirachta indica leaf extract (AAILE) was assessed against DMBA-induced hepatotoxicity. DMBA (7,12-dimethylbenz[a] anthracene) treatment (40 mg/kg body weight, ip) to male Balb/c mice resulted in the derailment of liver function as revealed by extremely slow clearance of 99mTc-mebrofenin from liver, elevated levels of alkaline phosphatase (ALP) and al...

Ovarian follicle disruption in mice caused by 7,12-dimethylbenz[a]anthracene (DMBA) is attributed to its bioactivation by CYP1B1 to a 3,4-epoxide which is then hydrolyzed to form a 3,4-diol by microsomal epoxide hydrolase (mEH). Further epoxidation by CYP1A1 or 1B1 forms the ultimate ovotoxicant, DMBA-3,4-diol-1,2-epoxide. Studies suggest that the mouse ovary expresses these enzymes, and thus, ...

Objective: To determine the effect of electro-acupuncture (EA) treatment on serum levels of interferon-γ (IFN-γ) in rats with 7,12-dimethylbenz(α)anthracene (DMBA)-induced breast tumors. Methods: Twenty five female Wistar rats were divided randomly into 5 groups: normal group (N; neither DMBA-induced nor treated with EA); control group (C; DMBA-induced only); EA 3 days : (DMBA-induced + EA for ...

We investigated the effects of quercetin on 7,12-dimethylbenz(a)anthracene (DMBA)-induced oxidative stress and the expression of CYP1A1 and CYP1B1 in mice. Quercetin was administered orally to mice at 100 or 250 mg/kg BW for 18 days, after which DMBA (34 mg/kg BW) was administered intragastrically twice. Quercetin showed side effects such as increased aspartate aminotransferase (AST) and alanin...

10-Fluoro-7,12-dimethylbenz(a)anthracene (10-F-DMBA) is a more potent skin tumor initiator in SENCAR mice when com pared with the parent hydrocarbon 7,12-dimethylbenz(a)anthracene (DMBA). To elucidate the mechanism for this difference, the covalent binding of these two hydrocarbons to the DMA of mouse epidermal cells in vivo and in vitro was compared. The quantity of 10-F-DMBA covalently bound ...

We examined the role of UVR (UV radiation) (UVA, 320-400 nm; UVB, 290-320 nm; and the combination of UVA and UVB) as a promoter in the induction of cutaneous melanoma. One hundred and seventy hairless mice (Skh-hr2), 6-8 weeks old, were treated in 8 groups: group I, DMBA [7,12-dimethylbenz(a)anthracene] plus UVA; group II, DMBA plus UVA plus UVB; group III, DMBA plus UVB; group IV, DMBA; group ...

Xeroderma pigmentosum group A (XPA) gene-deficient mice easily developed skin cancers by the application of topical chemical carcinogens as well as by UV irradiation. As certain chemical carcinogens have been shown to be immunosuppressive, we examined the inflammatory and immunosuppressive effects of dimethylbenz(a)anthracene (DMBA) on XPA mice. Compared with wild-type mice, XPA mice showed gre...

Estrogenic status is thought to influence the cancer risk in women and has been reported to affect toxicity of carcinogenic polycyclic aromatic hydrocarbons (PAHs) in animals. The objective of this study was to examine the influence of estradiol (E2) on hepatic gene expression changes mediated by 7,12-dimethylbenz(a)anthracene (DMBA), a potent PAH. Sprague-Dawley rats were ovariectomized on pos...

Large doses of 7,12-dimethylbenz[a]anthracene (7,12-DMBA) caused the death of rats within 1 day. A small amount of any of 5 polynuclear aromatic hydrocarbons or of an aromatic amine given before the highly toxic dose of 7,12-DMBA resulted in survival for more than 2 months and the specific atrophy of testis which follows 7,12-DMBA was largely prevented. Among the protective aromatics is 7,12-DM...