Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.3.1.21 (CPT)
 4,580 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effect of insulin on the abundance of mRNAs coding for tyrosine aminotransferase (TAT; EC 2.6.1.5), tryptophan oxygenase (TO; EC 1.13.1.12), and P-enolpyruvate carboxykinase(GTP) (PEPCK; EC 4.1.1.32) was examined in primary cultures of adult rat hepatocytes and in FTO-2B rat hepatoma cells by Northern blot analysis using RNA probes made from SP6-cDNAs. Insulin (10(-11)-10(-7) M), which has been reported to induce TAT and decrease the activity of TO, did not change the levels of TAT mRNA and TO mRNA in hepatocytes regardless of the presence of other inducers. In the same cells, dexamethasone increased TAT mRNA up to 19-fold and TO mRNA up to 15-fold, and 8pClPhS-cAMP (CPT-cAMP) raised the level of TAT mRNA up to 36-fold. The abundance of TO mRNA was not altered by CPT-cAMP. In contrast to TAT mRNA and TO mRNA, the level of PEPCK mRNA was dramatically decreased by insulin in the same hepatocytes. The sensitivity to this inhibitory effect of insulin was enhanced by dexamethasone and reduced by CPT-cAMP. FTO-2B hepatoma cells, which do not express detectable levels of TO mRNA, showed responses similar to those of hepatocytes, except that insulin caused a moderate reduction in TAT mRNA, but only in the presence of CPT-cAMP. The PEPCK mRNA in FTO-2B cells was suppressed by insulin in a manner closely resembling the effects in hepatocytes in the present study and in H4IIE hepatoma cells previously reported.
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PMID:Regulation of gene expression in rat hepatocytes and hepatoma cells by insulin: quantitation of messenger ribonucleic acid's coding for tyrosine aminotransferase, tryptophan oxygenase, and phosphoenolpyruvate carboxykinase. 287 68

The effect of anisoosmolarity on the abundance of various mRNA species was examined in perfused rat liver and H4IIE rat hepatoma cells. Hyperosmotic exposure (385 mosmol/l) of isolated rat livers increased mRNA levels for tyrosine aminotransferase (TAT) by 246% and those for phosphoenolpyruvate carboxykinase (PEPCK) by 186%, whereas hypoosmotic exposure (225 mosmol/l) decreased their levels to 43% and 42%, respectively. mRNA levels for fructose-1,6-bisphosphatase (FBP), argininosuccinate lyase (ASL), argininosuccinate synthetase (ASS), glutamine synthetase (GS), glutaminase (GA) and glucokinase (GK) were largely unaffected. In H4IIE cells the modulation of TAT and PEPCK mRNA levels by anisoosmotic exposure was similar to that found in perfused rat liver. ASL and glutaminase mRNA levels were influenced in an opposite manner. The effects of anisoosmolarity on PEPCK mRNA levels in H4IIE cells were largely abolished in the presence of the protein kinase inhibitors H-7, H-89 and HA-1004. Other protein kinase inhibitors such as Go-6850, KN-62, Rp-8-CPT-cAMPS, rapamycin, wortmannin, genistein or herbimycin did not prevent the osmosensitivity of PEPCK mRNA levels. Also pertussis and cholera toxin, vanadate and colchicine did not affect the osmosensitivity of PEPCK mRNA levels. The data suggest that anisoosmotic exposure acts on the levels of some but not all mRNA species and that this action may involve changes in protein phosphorylation. They further indicate that the recently identified osmosensitive signal transduction pathway which involves a G-protein and tyrosine kinase dependent activation of mitogen-activated protein kinases is apparently not involved in the osmoregulation of PEPCK mRNA levels.
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PMID:Anisoosmotic regulation of hepatic gene expression. 892 14