title: Prolonged induction of hepatic ornithine decarboxylase and its relation to cyclic adenosine 3':5'-monophosphate-dependent protein kinase activation after a single administration of diethylnitrosamine.
abstract: After a single injection of diethylnitrosamine (200 mg/kg), there was a rapid increase in the activity ratio of hepatic cyclic adenosine 3':5'-monophosphate (cyclic AMP)-dependent protein kinase (within 1 hr) followed by the induction of ornithine decarboxylase which was detectable by 3 hr. Both the cyclic AMP-dependent protein kinase activity ratio and the activity of ornithine decarboxylase were significantly elevated above controls for 7 days following the administration of diethylnitrosamine. A single noncarcinogenic dose of diethylnitrosamine (25 mg/kg) did not increase the cyclic AMP-dependent protein kinase activity ratio or induce ornithine decarboxylase activity at 24 hr postadministration. However, serial administration of diethylnitrosamine (25 mg/kg) for 4 or 7 days resulted in an increased activity ratio of cyclic AMP-dependent protein kinase and increased ornithine decarboxylase activity. This is the first report of a prolonged increase in both the activity ratio of hepatic cyclic AMP-dependent protein kinase and the activity of ornithine decarboxylase in response to a single carcinogenic dose of diethylnitrosamine.
mesh_terms: D000818:Animals; D002262:Carboxy-Lyases / Q000096:biosynthesis*; D000242:Cyclic AMP / Q000378:metabolism*; D004052:Diethylnitrosamine / Q000008:administration & dosage*; D004305:Dose-Response Relationship, Drug; D004789:Enzyme Activation / Q000187:drug effects; D007527:Isoenzymes / Q000378:metabolism; D008099:Liver / Q000187:drug effects* / Q000378:metabolism; D008114:Liver Neoplasms, Experimental / Q000209:etiology; D008297:Male; D009602:Nitrosamines / Q000008:administration & dosage*; D009955:Ornithine Decarboxylase / Q000096:biosynthesis*; D011494:Protein Kinases / Q000378:metabolism*; D051381:Rats; D013997:Time Factors
chemical_list: D007527:Isoenzymes; D009602:Nitrosamines; D004052:Diethylnitrosamine; D000242:Cyclic AMP; D011494:Protein Kinases; D002262:Carboxy-Lyases; D009955:Ornithine Decarboxylase