title: Inhibitory effect of actinomycin D on the inductio of rat mammary tumors by in vitro exposure to 7,12-dimethylbenz(a)anthracene.
abstract: The inhibitory effect of actinomycin D on the induction of tumors by in vitro exposure of mammary glands to 7,12-dimethylbenz(a)anthracene was studied. When actinomycin D was given i.p. 24 hr before excision of the mammary glands, the induction of tumors by in vitro  exposure of the glands to 7,12-dimethylbenz(a)anthracene was significantly decreased. On the other hand, when actinomycin D was administered 24 hr after excision, it had no effect on the induction of tumors. In vitro exposure of excised glands to 7,12-dimethylbenz(a)anthracene and actinomycin D significant decreased tumor induction. However, the order of exposure to 7,12-dimethylbenz(a)anthracene and actinomycin D influenced the inhibitory effect of actinomycin D on tumor induction. Results indicated that this might be due to a difference in the amounts of 7,12-dimethylbenz(a)anthracene and actinomycin D bound to the mammary glands.
mesh_terms: D015127:9,10-Dimethyl-1,2-benzanthracene / Q000008:administration & dosage / Q000037:antagonists & inhibitors* / Q000378:metabolism; D000818:Animals; D001551:Benz(a)Anthracenes / Q000037:antagonists & inhibitors*; D003609:Dactinomycin / Q000008:administration & dosage / Q000378:metabolism / Q000494:pharmacology*; D005260:Female; D008321:Mammary Glands, Animal / Q000378:metabolism; D008325:Mammary Neoplasms, Experimental / Q000139:chemically induced* / Q000378:metabolism / Q000517:prevention & control; D051381:Rats
chemical_list: D001551:Benz(a)Anthracenes; D003609:Dactinomycin; D015127:9,10-Dimethyl-1,2-benzanthracene