title: Action of brassinosteroids on the epithelial cell line from Chironomus tentans.
abstract: The two brassinosteroids, 22 S,23 S-homobrassinolide and 22 S,23 S-homocastasterone are weak competitors of the binding of [3H]ponasterone A to the intracellular ecdysteroid receptor from the epithelial cell line from Chironomus tentans. The relative affinities to the ecdysteroid receptor are 0.001 for both brassinosteroids as compared to 20-OH-ecdysone and 0.1 in comparison to ecdysone. Both substances exert morphological effects similar to those observed with 20-OH-ecdysone. Like moulting hormones both brassinosteroids inhibit chitin synthesis. However, these effects were observed only at rather high concentrations (10(-5) to 10(-4) M) which were cytotoxic for 22 S,23 S-homobrassinolide.
authors.affiliation: Institut für Zoologie, Heinrich-Heine-Universität Düsseldorf, Bundesrepublik Deutschland.
authors.forename: K D
authors.initials: KD
authors.lastname: Spindler
authors.forename: M
authors.initials: M
authors.lastname: Spindler-Barth
authors.forename: A
authors.initials: A
authors.lastname: Turberg
authors.forename: G
authors.initials: G
authors.lastname: Adam
mesh_terms: D000110:Acetylcholinesterase / Q000378:metabolism*; D000818:Animals; D001667:Binding, Competitive; D002460:Cell Line; D002683:Chironomidae; D002686:Chitin / Q000096:biosynthesis*; D002778:Cholestanones / Q000494:pharmacology*; D004441:Ecdysterone / Q000031:analogs & derivatives / Q000378:metabolism; D004847:Epithelial Cells; D004848:Epithelium / Q000187:drug effects / Q000378:metabolism; D007700:Kinetics; D011987:Receptors, Steroid / Q000187:drug effects / Q000378:metabolism*
chemical_list: D002778:Cholestanones; D011987:Receptors, Steroid; C034808:ecdysteroid receptor; D002686:Chitin; D004441:Ecdysterone; C070163:homobrassinolide; C070164:homocastasterone; C008999:ponasterone A; D000110:Acetylcholinesterase