Tyrosine aminotransferase: enzyme induction independent of adenosine 3', 5'-monophosphate.
The importance of adenyl cyclase and adenosine 3',5'-monophosphate in the induction of tyrosine aminotransferase by adrenocorticosteroids has been tested in HTC cells derived from a rat hepatoma and grown in tissue culture. Adrenocorticosteroids cause a 10-to 15-fold increase in the rate of synthesis of tyrosine aminotransferase in these cells. Under various experimental conditions, with or without glucocorticoids, neither adenyl cyclase nor cyclic adenosine mono-phosphate could be detected in HTC cells. In addition, neither the cyclic nucleotide nor N(6), O(2')-dibutyryl cyclic adenosine monophosphate caused increased activity of the transaminase in HTC cells. We conclude that induction of tyrosine aminotransferase by glucocorticoids is not mediated by the adenyl cyclase-cyclic adenosine monophosphate system.
D000227:Adenine Nucleotides; D000262:Adenylyl Cyclases; D000818:Animals; D006528:Carcinoma, Hepatocellular; D046508:Culture Techniques; D000242:Cyclic AMP; D003907:Dexamethasone / Q000494:pharmacology; D004790:Enzyme Induction; D004798:Enzymes; D005459:Fluorides / Q000494:pharmacology; D005934:Glucagon / Q000494:pharmacology; D005938:Glucocorticoids / Q000494:pharmacology*; D008113:Liver Neoplasms; D009374:Neoplasms, Experimental; D051381:Rats; D013806:Theophylline / Q000494:pharmacology; D014444:Tyrosine Transaminase / Q000096:biosynthesis*
D000227:Adenine Nucleotides; D004798:Enzymes; D005938:Glucocorticoids; D003907:Dexamethasone; D005934:Glucagon; D013806:Theophylline; D000242:Cyclic AMP; D014444:Tyrosine Transaminase; D000262:Adenylyl Cyclases; D005459:Fluorides