EPINEPHRINE-INDUCED REDUCTION IN INSULIN-RECEPTOR MESSENGER-RNA LEVELAND STABILITY IN U-937 HUMAN PROMONOCYTIC CELLS

The administration of 10(-5) M epinephrine transiently decreased insul in receptor (IR) mRNA levels in U-937 human promonocytic cells, which reached their minimum value after 24 hours. Such a decrease seems to b e due, at least in part, to a reduction in transcript stability, since the IR mRNA half-life was observed to decline from approximately 4 h in untreated cells to 3 h in epinephrine-treated cells. Computer inspe ction of the sequence of the 3' untranslated region of the human IR mR NA 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.