Inactivation of hamster uterine estrogen receptor was assayed in nuclear KCl extracts (30 min, 37°C, pH 7.5) after progesterone treatment invivo for 2h. At very low concentrations (>0.05 mM), molybdate and vanadate blocked the progesterone-induced increase in receptor inactivation. In contrast, only high concentrations (>10 mM) of the inhibitors blocked receptor inactivation in extracts from untreated hamsters. Gel electrophoresis and inhibition curves for phosphatases in nuclear extract demonstrated that acid, rather than alkaline, phosphatase activity is most likely responsible for these effects. These data suggest that progesterone antagonizes estrogen action in the hamster uterus by promoting estrogen receptor dephosphorylation leading to inactivation.
|Original language||English (US)|
|Number of pages||7|
|Journal||Biochemical and Biophysical Research Communications|
|State||Published - Jan 29 1982|
ASJC Scopus subject areas
- Molecular Biology
- Cell Biology