Figure 5. Dexamethasone stimulated TH gene transcription and induced TH mRNA and TH protein in MN9D cells.

(A) MN9D cells were treated with different concentrations of dexamethasone for 24 hr and TH mRNA and TH primary transcripts were measured using semiquantitative RT-PCR (for the autoradiogram) and quantitative RT-PCR (for the complete concentration-response curve). The data represent the means ± SE from 3 dishes. Dexamethasone concentrations of 30 uM or greater yielded significant increases in both TH mRNA and TH RNA primary transcripts (p < .05). (B) MN9D cells were treated with 0.1 uM dexamethasone for different periods of time and TH mRNA and TH RNA primary transcripts were measured using quantitative RT-PCR. The data represent the means ± SE from 6 dishes. (D) MN9D cells were treated with 0.1 uM dexamethasone for different periods of time and TH protein was measured using western analysis and TH activity was assayed using 4 mM 6MPH₄. The data represents the means ± SE from 3 dishes. (D) MN9D cells were treated with 0.1 uM dexamethasone in the presence or absence of different concentrations of mifepristone for 24 hr. TH RNA primary transcripts expressing genomic intron-2 sequences (filled squares) and mature TH mRNA transcripts (filled circles) were measured using quantitative RT-PCR. GAPDH mRNA transcripts were also measured using this assay and these values were used for normalization purposes. Values for TH RNA primary gene transcripts in control and dexamethasone-treated cells (without mifepristone) and expressed as fold-increases) were 1.0 ± 0.1 and 1.9 ± 0.2, respectively (p < .05). Values for TH mRNA transcripts in control and dexamethasone-treated cells were 1.0 ± 0.1 and 2.5 ± 0.2, respectively (p < .01). The data represent the means ± SE from 5–6 dishes.

a: p < .05 compared to control values.