Inhibition of 7,12-dimethylbenzanthracene-induced rat mammary tumor growth by 2,3,7,8-tetrachlorodibenzo-p-dioxin.
2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) and related compounds inhibit diverse estrogen-induced responses in the rodent uterus and human breast cancer cells. The effects of a single non-toxic dose of TCDD (10 micrograms/kg) on the development of mammary tumors was investigated in female Sprague-Dawley rats treated with an oral dose of 7,12-dimethylbenzanthracene (DMBA) (20 mg). In rats which developed mammary tumors, subsequent treatment with corn oil (vehicle) resulted in a 3.9-fold increase in mammary tumor volume after 21 days. In contrast, a second group of rats with mammary tumors were treated with a non-toxic dose of TCDD (10 micrograms/kg) and after 21 days, the mean tumor volumes decreased from 89.7 +/- 53 mm3 to 24.9 +/- 28.5 mm3. Moreover, these results demonstrate the antitumorigenic activity of TCDD in female Sprague-Dawley rats.
Holcomb
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Texas A&M University, College Station 77843-4466.
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D015127:9,10-Dimethyl-1,2-benzanthracene; D000818:Animals; D005260:Female; D008325:Mammary Neoplasms, Experimental / Q000139:chemically induced / Q000517:prevention & control*; D000072317:Polychlorinated Dibenzodioxins / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley
D000072317:Polychlorinated Dibenzodioxins; D015127:9,10-Dimethyl-1,2-benzanthracene