title: Involvement of reactive oxygen species in PTTH-stimulated ecdysteroidogenesis in prothoracic glands of the silkworm, Bombyx mori.
abstract: In the present study, the possible involvement of reactive oxygen species (ROS) in prothoracicotropic hormone (PTTH)-stimulated ecdysteroidogenesis of Bombyx mori prothoracic glands (PGs) was investigated. Results showed that PTTH treatment resulted in a rapidly transient increase in the intracellular ROS concentration, as measured using 2',7'-dichlorofluorescin diacetate (DCFDA), an oxidation-sensitive fluorescent probe. The antioxidant, N-acetylcysteine (NAC), abolished PTTH-induced increase in fluorescence. Furthermore, PTTH-induced ROS production was partially inhibited by the NAD(P)H oxidase inhibitor, apocynin, indicating that NAD(P)H oxidase is one of the sources for PTTH-stimulated ROS production. Four mitochondrial oxidative phosphorylation inhibitors (rotenone, antimycin A, the uncoupler carbonyl cyanide p-trifluoromethoxyphenylhydrazone (FCCP), and diphenylene iodonium (DPI)) significantly attenuated ROS production induced by PTTH. These data suggest that the activity of complexes I and III in the electron transport chain and the mitochondrial inner membrane potential (ΔΨ) contribute to PTTH-stimulated ROS production. In addition, PTTH-stimulated ecdysteroidogenesis was greatly inhibited by treatment with either NAC or mitochondrial inhibitors (rotenone, antimycin A, FCCP, and DPI), but not with apocynin. These results indicate that mitochondria-derived, but not membrane NAD(P)H oxidase-mediated ROS signaling, is involved in PTTH-stimulated ecdysteroidogenesis of PGs in B. mori.
authors.affiliation: Department of Biology, National Museum of Natural Science, 1 Kuan-Chien Road, Taichung 404, Taiwan, ROC.
authors.forename: Yun-Chin
authors.initials: YC
authors.lastname: Hsieh
authors.forename: Shih-Lan
authors.initials: SL
authors.lastname: Hsu
authors.forename: Shi-Hong
authors.initials: SH
authors.lastname: Gu
mesh_terms: D000818:Animals; D012831:Bombyx / Q000235:genetics / Q000378:metabolism*; D026461:Ecdysteroids / Q000378:metabolism*; D004702:Endocrine Glands / Q000378:metabolism; D007301:Insect Hormones / Q000378:metabolism*; D017382:Reactive Oxygen Species / Q000378:metabolism*; D015398:Signal Transduction
chemical_list: D026461:Ecdysteroids; D007301:Insect Hormones; D017382:Reactive Oxygen Species; C009089:prothoracicotropic hormone
keywords: Bombyx mori; Ecdysteroids; Mitochondrial electron transport chain; PTTH; ROS signaling