Insulin antagonism of dexamethasone induction of tyrosine aminotransferase in cultured fetal hepatocytes: A correlation between enzyme activity, synthesis, level of messenger RNA and transcription

Max H. CAKE, Kevin K.W. HO, Leslie SHELLY, Elizabeth MILWARD, George C.T. YEOH

    Research output: Contribution to journalArticle

    21 Citations (Scopus)

    Abstract

    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.

    Original languageEnglish
    Pages (from-to)429-435
    Number of pages7
    JournalEuropean Journal of Biochemistry
    Volume182
    Issue number2
    DOIs
    Publication statusPublished - 1 Jan 1989

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