title: Effects of the compounds 2-methoxynaphthoquinone, 2-propoxynaphthoquinone, and 2-isopropoxynaphthoquinone on ecdysone 20-monooxygenase activity.
abstract: The effects of the natural compound 2-methoxy-1,4-naphthoquinone, isolated from the leaves of Impatiens glandulifera and the synthetic compounds 2-propoxy-1,4-naphthoquinone and 2-isopropoxy-1,4-naphthoquinone on ecdysone 20-monooxygenase (E-20-M) activity were examined in three insect species. Homogenates of wandering stage third instar larvae of Drosophila melanogaster, or abdomens from adult female Aedes aegypti, or fat body or midgut from fifth instar larvae of Manduca sexta were incubated with radiolabelled ecdysone and increasing concentrations (from 1 x 10(-8) to 1 x 10(-3) M) of the three compounds. All three compounds were found to inhibit in a dose-dependent fashion the E-20-M activity in the three insect species. The concentration of these compounds required to elicit a 50% inhibition of this steroid hydroxylase activity in the three insect species examined ranged from approximately 3 x 10(-5) to 7 x 10(-4) M.
authors: Department of Biology and Health Services, Edinboro University of Pennsylvania, Edinboro, Pennsylvania, USA.
authors: Martin J
authors: MJ
authors: Mitchell
authors: Aaron I
authors: AI
authors: Brescia
authors: Stan L
authors: SL
authors: Smith
authors: E David
authors: ED
authors: Morgan
mesh_terms: D000330:Aedes / Q000187:drug effects / Q000201:enzymology; D000818:Animals; D001189:Aryl Hydrocarbon Hydroxylases / Q000037:antagonists & inhibitors*; D004305:Dose-Response Relationship, Drug; D004331:Drosophila melanogaster / Q000187:drug effects / Q000201:enzymology; D005260:Female; D029069:Impatiens / Q000737:chemistry; D007814:Larva / Q000187:drug effects / Q000201:enzymology; D018402:Manduca / Q000187:drug effects / Q000201:enzymology; D015394:Molecular Structure; D009285:Naphthoquinones / Q000737:chemistry / Q000494:pharmacology*; D018515:Plant Leaves / Q000737:chemistry; D013250:Steroid Hydroxylases / Q000037:antagonists & inhibitors*
chemical_list: C528195:2-isopropoxynaphthoquinone; C528193:2-methoxynaphthoquinone; C528194:2-propoxynaphthoquinone; D009285:Naphthoquinones; D013250:Steroid Hydroxylases; D001189:Aryl Hydrocarbon Hydroxylases; C020095:ecdysone 20-hydroxylase