Insulin antagonism of dexamethasone induction of tyrosine aminotransferase in cultured fetal hepatocytes. A correlation between enzyme activity, synthesis, level of messenger RNA and transcription
Cake, M.H., Ho, K.K.W., Shelly, L., Milward, E. and Yeoh, G.C.T. (1989) Insulin antagonism of dexamethasone induction of tyrosine aminotransferase in cultured fetal hepatocytes. A correlation between enzyme activity, synthesis, level of messenger RNA and transcription. European Journal of Biochemistry, 182 (2). pp. 429-435.
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Previous studies have shown that insulin depresses the induction of tyrosine aminotransferase by glucocorticoids in cultured fetal rat hepatocytes. However, the site at which this inhibitory effect is exerted was not elucidated, since only enzyme activity was determined in such studies. Therefore, the effet of insulin on tyrosine aminotransferase synthesis, the level of its mRNA as well as the rate of transcription of the gene in isolated nuclei have been determined. The results obtained indicate that in cultures exposed to dexamethasone, Bt2cAMP, insulin and combinations of these additives, there is an excellent correlation between the enzyme activity, enzyme synthesis and the level of mRNA. Run-on transcription experiments indicate that the reduction in the level of mRNA by insulin in dexamethasone-supplemented cultures is the result of a diminished rate of gene transcription.
|Publication Type:||Journal Article|
|Murdoch Affiliation:||School of Biological and Environmental Sciences|
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