Figure 1.

A, Glucocorticoids specifically induce human αGSU gene expression in LβT2 gonadotrope cells. LβT2 cells were transiently cotransfected with the 1.8-kb αGSU-luc reporter gene and with 200 ng of the respective receptor expression vectors indicated on the graph. The cells were serum starved overnight and then treated with 100 nm R1881 (synthetic androgen), R5020 (synthetic progesterone), Dex (synthetic glucocorticoid), or 17β-estradiol for 24 h. Luciferase activity was assayed and normalized to β-galactosidase activity and shown relative to the empty reporter vector. B, The 1.8-kb αGSUluc reporter gene was transiently transfected into LβT2 cells without (endogenous GR) or with (exogenous GR) the GR expression vector. The cells were serum starved overnight and then treated for 24 h with 100 nm corticosterone, a natural glucocorticoid, or Dex, a synthetic glucocorticoid. C, The 1.8-kb αGSUluc reporter gene was transiently transfected into LβT2 cells without (endogenous GR) or with (exogenous GR) the GR expression vector. The cells were serum starved overnight and then treated for 24 h with the indicated Dex concentrations (100 pm to 1 μm). Data represent the mean ± sem of at least three experiments performed in triplicate and are presented as fold induction relative to the vehicle control. *, Dex induction is significantly different from the vehicle-treated control, Student’s t test, P < 0.05.