Rapid inhibition of c-myc gene expression by a glucocorticoid in the avian oviduct

Charles Rories, Chu Kwan Lau, Karen Fink, Thomas C. Spelsberg

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20 Scopus citations


The glucocorticoid dexamethasone (DEX) causes a rapid, reversible reduction in c-myc mRNA level in the oviducts of estrogen-treated, immature chickens. The c-myc mRNA level begins to decrease by 5 min after injection of 0.5 mg DEX, reaches a minimum of 10% of the control value by 30 min, and returns to 30-40% of the control value by 4 h post injection. This rapid effect of DEX on the c-myc mRNA level occurs in both diethylstilbestrol-stimu-lated and diethylstilbestrol-withdrawn oviducts. The effect is dose dependent, with reduction of the c-myc mRNA measured with as little as 10 µg DEX injection (0.03 µg/g BW). The effect of the steroid is gene specific with H2B histone mRNA displaying a significantly reduced response. The effect is also tissue specific with liver displaying an increase of 170% of control values in c-myc mRNA level by 30 min after injection of 0.5 mg DEX. The reduction of avian oviduct c-myc mRNA levels by DEX may play a role in glucocorticoid inhibition of cell proliferation in this tissue. The rapidity of the steroid effects on c-myc expression makes it likely that the steroid-induced reduction of c-myc mRNA levels represents a direct primary action of the steroid-receptor complex on the c-myc gene expression.

Original languageEnglish (US)
Pages (from-to)991-1001
Number of pages11
JournalMolecular Endocrinology
Issue number6
StatePublished - Jun 1989

ASJC Scopus subject areas

  • Molecular Biology
  • Endocrinology


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