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Ovaries from female adults of Gryllus bimaculatus produce considerable amounts of free and conjugated ecdysteroids in vitro. The rate of ecdysteroid synthesis after a 16 h incubation in Grace's medium, changes during vitellogenesis in a characteristic way, reaching a peak value of about 5 ng per hour, per animal, at days 415 after ecdysis, when animals start to deposit eggs. During incubation of pieces of the female abdominal integument together with the adjacent segmental fat body, a net synthesis of moulting hormones is observed, similar to that in the ovary. Ecdysteroid production by integument starts shortly after the imaginal moult and also reaches a maximum of about 3 ng per hour, per animal, around days 415 after ecdysis. Both tissues mainly synthesize and release ecdysone into the incubation medium. From tissues of male adult crickets only the abdominal integument shows a significant net synthesis of ecdysteroids. In vitro incubations of egg homogenates of various ages result in a net synthesis of free and conjugated ecdysteroids in older embryos, with a maximum one day before hatching of the larva. The imidazole compound KK-42 does not inhibit ecdysteroid synthesis in vitro in cricket embryos.

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