OBJECTIVE: Hyperinsulinemia and insulin resistance are implicated in the pathophysiology of polycystic ovary syndrome, a condition associated with elevated levels of LH. We tested the hypothesis that insulin enhances the transcriptional activity of LHbeta promoter. STUDY DESIGN: We transfected the gonadotrope cell line LbetaT2 with a plasmid that expresses the proximal promoter of LHbeta gene upstream of luciferase, and determined insulin effect on endogenous LHbeta mRNA. RESULTS: We found that insulin stimulated (2-4 fold) the activity of this promoter in a time- and concentration-dependent manner. Accordingly, insulin up-regulated the level of LHbeta mRNA. In contrast, insulin had no significant effect on GnRH-dependent LHbeta expression. The expression of Egr-1 and SF-1, which are essential for transcription of LHbeta gene, was unchanged by insulin. CONCLUSION: Insulin enhances the transcription of LHbeta gene. This modulation may contribute to the pathophysiology of polycystic ovary syndrome.
OBJECTIVE:Hyperinsulinemia and insulin resistance are implicated in the pathophysiology of polycystic ovary syndrome, a condition associated with elevated levels of LH. We tested the hypothesis that insulin enhances the transcriptional activity of LHbeta promoter. STUDY DESIGN: We transfected the gonadotrope cell line LbetaT2 with a plasmid that expresses the proximal promoter of LHbeta gene upstream of luciferase, and determined insulin effect on endogenous LHbeta mRNA. RESULTS: We found that insulin stimulated (2-4 fold) the activity of this promoter in a time- and concentration-dependent manner. Accordingly, insulin up-regulated the level of LHbeta mRNA. In contrast, insulin had no significant effect on GnRH-dependent LHbeta expression. The expression of Egr-1 and SF-1, which are essential for transcription of LHbeta gene, was unchanged by insulin. CONCLUSION:Insulin enhances the transcription of LHbeta gene. This modulation may contribute to the pathophysiology of polycystic ovary syndrome.
Authors: Bronwen Martin; Erin Golden; Olga D Carlson; Josephine M Egan; Mark P Mattson; Stuart Maudsley Journal: Ageing Res Rev Date: 2008-02-07 Impact factor: 10.895
Authors: David J Arriola; Susan L Mayo; Danalea V Skarra; Courtney A Benson; Varykina G Thackray Journal: J Biol Chem Date: 2012-08-03 Impact factor: 5.157