Zeitschrift fuer Naturforschung. Section C 1992-01-01

Action of brassinosteroids on the epithelial cell line from Chironomus tentans.

K D Spindler, M Spindler-Barth, A Turberg, G Adam

Index: Z. Naturforsch., C, J. Biosci. 47(3-4) , 280-4, (1992)

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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.