Cricket, Gryllus bimaculatus
Springer Online Journal Archives 1860-2000
Summary Ovaries from 4-day-old female adults of Gryllus bimaculatus produce about 5 ng of free and conjugated ecdysteroids per hour during a 16-h incubation in Grace's medium. During incubation of pieces of the abdominal integument together with the adjacent segmental fat body, a net synthesis of moulting hormones is observed (2.3 ng per hour per animal), similar to that in the ovary. Separate incubations of disunited abdominal epidermis and segmental fat body tissue result in much lower rates of ecdysteroid synthesis. Ecdysteroid synthesis in ovarian homogenates is about one-third of that in intact organs. This reduction is due to a lack of conjugate formation in homogenates. Homogenates of the abdominal integument complex are no longer capable of synthesizing ecdysteroids. For both tissues, a de novo synthesis of ecdysteroids is corroborated by following the in vitro incorporation of [14C]-label from cholesterol and [3H]-label from 2,22,25-trideoxyecdysone (5β-ketodiol), respectively, into free ecdysone. The rate of incorporation into ecdysone is only 0.0014% for cholesterol but 0.48% for 5β-ketodiol. Both tissues represent primary sources of ecdysteroids in female adult crickets.
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