Epinephrine-induced reduction in insulin receptor mRNA level and stability in U-937 human promonocytic cells

The administration of 10(-5) M epinephrine transiently decreased insulin receptor (IR) mRNA levels in U-937 human promonocytic cells, which reached their minimum value after 24 hours. Such a decrease seems to be due, at least in part, to a reduction in transcript stability, since the IR mRNA half-life was observed to decline from approximately 4h in untreated cells to 3 h in epinephrine-treated cells. Computer inspection of the sequence of the 3' untranslated region of the human IR mRNA showed nine AUUUA pentamers and three U-rich regions. These domains could be targets for a RNA-binding protein induced by treatment with epinephrine producing a destabilization of IR mRNA in U-937 cells.