Rat primary hepatocytes and H4 hepatoma cells display differential sensitivity to cyclic AMP at the level of expression of tyrosine aminotransferase.
We have shown that the sensitivity of isolated hepatocytes and H4 hepatoma cells to cyclic AMP is different. In terms of activation of tyrosine aminotransferase at mRNA and activity level in response to cyclic AMP, isolated hepatocytes are 10-fold more sensitive. Hepatocytes and H4 hepatoma cells show similar sensitivities to cyclic AMP at the level of protein kinase A activation and phosphorylation of cyclic AMP response element binding protein (CREB) and the differential sensitivity must reside at other sites. The consequences of these findings to studies of control phenomena at the transcriptional level is discussed.
Pickering
C S
CS
2.205 School of Biological Sciences, University of Manchester, Oxford Road, Manchester, M13 9PT, United Kingdom.
Watkins
R H
RH
Dickson
A J
AJ
D000818:Animals; D000242:Cyclic AMP / Q000494:pharmacology*; D017362:Cyclic AMP Response Element-Binding Protein / Q000378:metabolism; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism; D004790:Enzyme Induction; D008099:Liver / Q000187:drug effects* / Q000201:enzymology; D008114:Liver Neoplasms, Experimental / Q000201:enzymology*; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D014407:Tumor Cells, Cultured; D014444:Tyrosine Transaminase / Q000096:biosynthesis*
D017362:Cyclic AMP Response Element-Binding Protein; D000242:Cyclic AMP; D014444:Tyrosine Transaminase; D017868:Cyclic AMP-Dependent Protein Kinases