Figure 1.

c-Jun is induced rapidly by GnRH. A, LβT2 cells were treated with 100 nM GnRH and total RNA was obtained after indicated time. Following reverse transcription, real-time quantitative PCR was carried out and the amount calculated according to the standard curve performed with c-Jun cDNA. The amount of c-Jun was normalized to the amount of GAPDH in each sample and the results were presented as fold induction for vehicle treated samples. B, -974/+236 and -974/+26 of the c-Jun promoter in pGL3 backbone were transfected into LβT2 cells with Herpes virus thymidine kinase-driven β-galactosidase gene as an internal control for transfection efficiency. After overnight starvation, cells were treated with vehicle or 100 nM GnRH and the amount of luciferase over β-galactosidase in GnRH treated samples were normalized to the ratio in vehicle treated samples for each reporter to determine GnRH fold induction. C, -974/+26 of the c-Jun promoter was transfected and after overnight starvation, cells were treated with vehicle or 100 nM GnRH, 50 nM insulin, 50 ng/ml EGF, 100 nM TPA, 1 μM forskolin, or 0.5 μM ionomycin for 5 hours, after which the luciferase and β-galactosidase values were obtained. * indicates significant induction by GnRH.