Regulation of catechol O-methyltransferase expression in granulosa cells: a potential role for follicular arrest in polycystic ovary syndrome

ObjectiveTo investigate the regulation of catechol O-methyltransferase (COMT) expression in granulosa cells and assess potential effects of 2-methoxyestradiol (2-ME2) and COMT inhibitors on granulosa cell steroidogenesis and proliferation.Design and SettingControlled experimental study in an academic research laboratory.Intervention(s)JC410 porcine and HGL5 human granulosa cell lines were used for in vitro experiments. Effects of 2-ME2 and COMT inhibitor treatment on DNA proliferation and steroidogenesis were assessed by using Hoechst dye and p450SCC-luciferase reporter assays. Effects of dihydrotestosterone (DHT), insulin, and all-trans retinoic acid (ATRA) on COMT messenger RNA expression were investigated by using COMTP1 promoter–luciferase reporter and Northern blot.Main Outcome Measure(s)Granulosa cell steroidogenesis and proliferation following COMP inhibitor and 2-ME2 treatment. Regulation of COMT expression with DHT, insulin, and ATRA.Result(s)2-Methoxyestradiol had a dual effect on granulosa cell proliferation and p450SCC- luciferase activity; low doses were stimulatory and high doses were inhibitory. Catechol O-methyltransferase inhibitor was associated with up to a 65% increase in JC410 cell number and a maximal 5.6-fold increase in p450SCC-luciferase activity at 20 μmol/L. Dihydrotestosterone, insulin, and ATRA all induced a dose-dependent increase in COMTP1-luciferase transactivation, as well as up-regulated COMT messenger RNA expression in granulosa cells.Conclusion(s)Catechol O-methyltransferase expression in granulosa cells was up-regulated by insulin, DHT, and ATRA. Catechol O-methyltransferase product, 2-ME2, decreased, whereas COMT inhibitor increased granulosa cell proliferation and steroidogenesis. These data suggest that COMT overexpression with subsequent increased level of 2-ME2 may lead to ovulatory dysfunction.