Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.7.1.1 (hexokinase)
 5,274 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The influence of dexamethasone on the isozyme patterns of ATP-hexose phosphotransferases, aldolase and pyruvate kinase of adult rat hepatocytes maintained in primary cultures has been studied. A progressive loss of the typical adult liver isozymes glucokinase, pyruvate kinase L and aldolase B, with a simultaneous increase of both pyruvate kinase A and hexokinase activities, was observed in hepatocytes cultured in the absence of added glucocorticoid. When the culture medium was supplemented with 10(-7)M dexamethasone, the adult liver patterns of pyruvate kinase and aldolase were preserved for at least seven days of culture, the initial level of glucokinase was maintained for three days, and the rise of hexokinase activity was delayed and partially blocked. These results are discussed in relation to the known beneficial effect of glucocorticoids on the survival of cultured hepatocytes.
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PMID:Effect of dexamethasone on the isozyme pattern of adult rat liver parenchymal cells in primary cultures. 711 Jan 29

The insulinoma beta-cell line INS-1 expresses the L-type pyruvate kinase gene at high level and responds to a rise in extracellular glucose by strong induction of gene expression. Following the addition of glucose to the culture medium in the 3.5-33 mM concentration range, the cellular level of L-type pyruvate kinase mRNA increases within 2 h and reaches a maximum 15-fold above basal in 8-12 h. By run-on nuclear assay, the relative transcription rate of the pyruvate kinase gene is shown to increase 4-fold at maximal stimulation, suggesting that both transcriptional and post-transcriptional effects contribute to mRNA accumulation. The glucose effect is totally suppressed by the hexokinase inhibitor mannoheptulose, indicating a requirement for glucose phosphorylation. The mRNA induction is not inhibited in glutamine-free culture medium or by azaserine, suggesting that the hexosamine biosynthetic pathway is not involved. Moreover, metabolism along the glycolytic pathway does not appear to be an absolute requisite, since 2-deoxyglucose partly mimics the inductive effect of glucose. The glucose effect on the pyruvate kinase gene is reversibly antagonized by agents increasing intracellular cAMP. In addition, the effect is highly specific to the pyruvate kinase gene. Neither proinsulin I mRNA nor glucokinase mRNA are increased in glucose-stimulated INS-1 cells. Short term transfection with CAT plasmids driven by the pyruvate kinase L promoter reveals specific glucose-inducible reporter activity with the 183-base pair promoter region upstream of the cap site. Within this region, the previously described L4 cis-acting element is crucial for glucose responsiveness, as demonstrated by the fact that a plasmid with a mutation in this element does not elicit glucose-inducible CAT activity. Induction of L-type pyruvate kinase mRNA occurs in the islets of rats subjected to fasting and carbohydrate refeeding. In conclusion, the L-type pyruvate kinase gene provides an interesting model of glucose-regulated gene in the endocrine beta-cell type.
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PMID:The pyruvate kinase gene as a model for studies of glucose-dependent regulation of gene expression in the endocrine pancreatic beta-cell type. 822 28