title: Independent induction and inhibition of ornithine decarboxylase and aryl hydrocarbon hydroxylase activities in rat epidermis.
abstract: Changes in the activities of ornithine decarboxylase (ODC) and aryl hydrocarbon hydroxylase (AHH) were investigated in rat epidermis after wounding the skin and application of 7,12-dimethylbenz(a)anthracene (DMBA), 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), and several enzyme inhibitors. Wounding of the skin by vigorous shaving led to a marked induction of ODC activity with a peak at 6 hr. Topical application of a single dose of tetradecanoylphorbol-13-acetate to wounded skin did not affect the activities of ODC and AHH. Application of single large dose (2.5 mg) of DMBA increased AHH activity 7-fold without affecting ODC activity. DL-alpha-difluoromethyl ornithine, a specific irreversible inhibitor of ODC, almost completely abolished ODC activity but did not inhibit DMBA- or TCDD-induced AHH activity. Several potential modifiers, including retinoic acid, indomethacin, 1,3-diamino-2-propranol, alpha-naphthoflavone, and SKF 525 A had unequal effects on ODC and AHH activities. These data indicate that ODC and AHH induction processes in the epidermis are independent biochemical events that are not causally related.
mesh_terms: D015127:9,10-Dimethyl-1,2-benzanthracene / Q000494:pharmacology; D000818:Animals; D001189:Aryl Hydrocarbon Hydroxylases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D002262:Carboxy-Lyases / Q000378:metabolism*; D000518:Eflornithine; D004790:Enzyme Induction; D004817:Epidermis / Q000201:enzymology*; D008297:Male; D009952:Ornithine / Q000031:analogs & derivatives / Q000494:pharmacology; D009955:Ornithine Decarboxylase / Q000378:metabolism*; D065108:Ornithine Decarboxylase Inhibitors; D000072317:Polychlorinated Dibenzodioxins / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D012867:Skin / Q000293:injuries; D013997:Time Factors
chemical_list: D065108:Ornithine Decarboxylase Inhibitors; D000072317:Polychlorinated Dibenzodioxins; D015127:9,10-Dimethyl-1,2-benzanthracene; D009952:Ornithine; D001189:Aryl Hydrocarbon Hydroxylases; D002262:Carboxy-Lyases; D009955:Ornithine Decarboxylase; D000518:Eflornithine