Henrich V C, Pak M D, Gilbert L I
Department of Biology, University of North Carolina, Chapel Hill 27514.
J Comp Physiol B. 1987;157(5):543-9. doi: 10.1007/BF00700973.
The larval ring gland of Drosophila melanogaster is the source of ecdysteroids responsible for larval-larval and larval-pupal molting. An extract prepared from the Drosophila larval central nervous system, that presumably contains prothoracicotropic hormone, elicits a significant and dose-dependent in vitro increase in ecdysteroid synthesis by ring glands from wandering third instar larvae. The synthesis of all three ecdysteroids previously identified as ring gland products is elevated by more than two-fold in the presence of neural extract. The maximum response occurs within 30 min and can be sustained for at least two hours after a 30 min exposure to neural extract. No non-neural tissue extracts evoke a response and most of the prothoracicotropic activity originates in the ventral ganglion. However, while extract prepared from larval brains elicits only a slight increase in ecdysteroid synthesis, it enhances the activity of a submaximal dose of ventral ganglion extract. This suggests that two or more neural factors, at least one from the brain lobes and another from the ventral ganglion, interact to stimulate ecdysteroid synthesis by the larval ring gland.
黑腹果蝇的幼虫环腺是负责幼虫-幼虫和幼虫-蛹蜕皮的蜕皮甾体的来源。从果蝇幼虫中枢神经系统制备的提取物，可能含有促前胸腺激素，能引起来自三龄游走幼虫的环腺在体外显著且剂量依赖性地增加蜕皮甾体的合成。在神经提取物存在的情况下，先前鉴定为环腺产物的所有三种蜕皮甾体的合成提高了两倍多。最大反应在30分钟内出现，并且在暴露于神经提取物30分钟后可以持续至少两小时。没有非神经组织提取物能引起反应，并且大多数促前胸腺活性起源于腹神经节。然而，虽然从幼虫脑制备的提取物仅引起蜕皮甾体合成的轻微增加，但它增强了亚最大剂量腹神经节提取物的活性。这表明两种或更多种神经因子，至少一种来自脑叶，另一种来自腹神经节，相互作用以刺激幼虫环腺的蜕皮甾体合成。
