title: Effect of triptolide on estradiol release from cultured rat granulosa cells.
abstract: Triptolide, a major active component of Tripterygium wilfordii Hook F (TWHF), is known to have multiple pharmacological activities. However, studies have also shown that triptolide is highly toxic to the reproductive system by disrupting normal androgen and estrogen signaling. In the present study, we investigated the effect of triptolide (5, 10, or 20 nM for 24 h) on estradiol production by rat granulosa cells. Triptolide inhibited basal and human chorionic gonadotropin (HCG)- or 8-bromo-cAMP-stimulated estradiol production as revealed by RIA assay. Furthermore, the HCG-evoked increase in cellular cAMP content was also inhibited by triptolide, indicating that disruption of the cAMP/PKA signaling pathway may mediate the deleterious effects of triptolide on steroid hormone regulation. In addition, (3)H(2)O tests showed that aromatase activity was significantly inhibited by triptolide in granulosa cells. Western blot and quantitative real-time PCR (qRT-PCR) assays further revealed that triptolide decreased protein and mRNA expression of aromatase in granulosa cells. Moreover, mRNA expression of luteinizing hormone receptor (LHR) was induced by triptolide also using qRT-PCR method. In contrast, cell viability tests using Cell Counting Kit-8 (CCK-8) and 3-(4,5-dimethyl-thiazol-2-yl)-2,5- diphenyl-tetrazolium bromide (MTT) method indicated that triptolide did not cause measurable cell death at doses that suppressed steroidogenesis. The reproductive toxicity of triptolide may be mainly caused by disruption of cAMP/PKA-mediated expression of estrogen synthesis enzymes, leading to reduced estradiol synthesis and reproductive dysfunction.
authors.affiliation: Jiangsu Center of Drug Screening, China Pharmaceutical University, Nanjing, PR China.
authors.forename: Juan
authors.initials: J
authors.lastname: Zhang
authors.forename: Li
authors.initials: L
authors.lastname: Liu
authors.forename: Xianmin
authors.initials: X
authors.lastname: Mu
authors.forename: Zhenzhou
authors.initials: Z
authors.lastname: Jiang
authors.forename: Luyong
authors.initials: L
authors.lastname: Zhang
mesh_terms: D000818:Animals; D001141:Aromatase / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D000242:Cyclic AMP / Q000378:metabolism; D017868:Cyclic AMP-Dependent Protein Kinases / Q000187:drug effects / Q000378:metabolism; D004224:Diterpenes / Q000494:pharmacology* / Q000633:toxicity; D004852:Epoxy Compounds / Q000494:pharmacology / Q000633:toxicity; D004958:Estradiol / Q000096:biosynthesis*; D005260:Female; D020869:Gene Expression Profiling; D006107:Granulosa Cells / Q000187:drug effects* / Q000378:metabolism; D007166:Immunosuppressive Agents / Q000494:pharmacology* / Q000633:toxicity; D010616:Phenanthrenes / Q000494:pharmacology* / Q000633:toxicity; D012333:RNA, Messenger / Q000032:analysis*; D051381:Rats; D017207:Rats, Sprague-Dawley; D060888:Real-Time Polymerase Chain Reaction; D011974:Receptors, LH / Q000187:drug effects / Q000235:genetics / Q000378:metabolism
chemical_list: D004224:Diterpenes; D004852:Epoxy Compounds; D007166:Immunosuppressive Agents; D010616:Phenanthrenes; D012333:RNA, Messenger; D011974:Receptors, LH; C001899:triptolide; D004958:Estradiol; D000242:Cyclic AMP; D001141:Aromatase; D017868:Cyclic AMP-Dependent Protein Kinases