Whisenton L R, Bowen M F, Granger N A, Gilbert L I, Bollenbacher W E
Gen Comp Endocrinol. 1985 May;58(2):311-8. doi: 10.1016/0016-6480(85)90347-8.
In the latter part of the last larval instar (Days 6-7) of Manduca sexta an increase in the hemolymph titer of juvenile hormone (JH) occurs which is involved in directing the pharate pupal development elicited by the large increase in the ecdysteroid titer on Days 7-8 of the instar. A time course analysis on Days 3-4 of the instar of both the first hemolymph ecdysteroid titer peak, which is responsible for wandering behavior and pupal commitment, and of the capacity of the corpora allata (CA) to synthesize JH I and III in vitro revealed a temporal correlation between the increasing ecdysteroid titer and a following increase in CA activity. The temporal arrangement of these increases suggested that ecdysteroids, i.e., 20-hydroxyecdysone, may elicit the increase in CA activity which contributes to the second increase in the JH titer during the latter part of the instar. Regulation of the CA by 20-hydroxyecdysone was investigated in vitro by assessing the effect of this ecdysteroid on JH I and III synthesis by CA incubated either as a complex with the brain-corpora cardiaca or as isolated glands. Dose-response analyses revealed that 20-hydroxyecdysone indeed had a stimulatory effect on JH synthesis by the CA, but only when the glands were complexed with the brain-corpora cardiaca. The effective concentration of 20-hydroxyecdysone was the same as the hemolymph concentration of the hormone at this time.(ABSTRACT TRUNCATED AT 250 WORDS)
在烟草天蛾最后一龄幼虫后期（第6 - 7天），其血淋巴中保幼激素（JH）滴度增加，这一过程参与引导由该龄期第7 - 8天蜕皮甾体滴度大幅增加所引发的蛹期发育。对该龄期第3 - 4天的首次血淋巴蜕皮甾体滴度峰值（负责幼虫的游走行为和蛹的形成）以及咽侧体（CA）体外合成JH I和III能力的时间进程分析显示，蜕皮甾体滴度的增加与随后CA活性的增加之间存在时间相关性。这些增加的时间安排表明，蜕皮甾体，即20 - 羟基蜕皮酮，可能引发CA活性的增加，这有助于该龄期后期JH滴度的第二次增加。通过评估20 - 羟基蜕皮酮对与脑 - 心侧体复合体一起孵育或作为分离腺体孵育时CA合成JH I和III的影响，对体外20 - 羟基蜕皮酮对CA的调节作用进行了研究。剂量 - 反应分析表明，20 - 羟基蜕皮酮确实对CA合成JH有刺激作用，但仅当腺体与脑 - 心侧体复合体结合时才起作用。此时20 - 羟基蜕皮酮的有效浓度与该激素在血淋巴中的浓度相同。（摘要截短至250字）
