Regulation of the ecdysteroid titer of Manduca sexta: reappraisal of the role of the prothoracic glands.
Regulation of the ecdysteroid titer of Manduca sexta: reappraisal of the role of the prothoracic glands.
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DOI：
10.1073/pnas.85.3.958
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发表时间：
1988-02
影响因子：
11.1
通讯作者：
J. T. Warren;S. Sakurai;D. B. Rountree;L. Gilbert;Shoei‐Sheng Lee;Koji Nakanishi
中科院分区：
文献类型：
--
作者：
J. T. Warren;S. Sakurai;D. B. Rountree;L. Gilbert;Shoei‐Sheng Lee;Koji Nakanishi
人们普遍认为昆虫的前胸腺产生蜕皮激素，它被周围组织中的20-单加氧酶转化为主要的蜕皮激素--20-羟基蜕皮酮。在含有血淋巴蛋白组分(HPF)的条件下，六纹夜蛾幼虫或幼虫的前胸腺在体外孵育时，培养液中蜕皮类固醇的含量增加了近8倍。当HPF被添加到含有前胸腺但腺体已被移除的培养液中时，也注意到了类似的增加。我们使用差示RIA显示，在体外前胸腺的一个主要产物与抗血清(20-羟基蜕皮酮-2-琥珀酸甲状腺球蛋白酰胺；H-2)发生交叉反应，该抗血清与具有修饰A环的蜕皮类固醇保持亲和力。然而，该产物不与主要与侧链修饰的蜕皮类化合物有亲和力的抗血清(蜕皮酮-22-琥珀酰甲状腺球蛋白酰胺；H-22)结合。我们利用体外前胸腺的放射性标记前体研究和结合的分析技术(核磁共振、CD、MS)证明，从胸腺释放的主要蜕皮激素是2-脱氢蜕皮酮和3-脱氢蜕皮酮(1：2)的混合物，在HPF存在下，它很快被还原为蜕皮激素。我们推测HPF的活性成分是3-β-3-β-(2-β)-Forin-3(2)-酮蜕皮激素还原酶。这些结果可能解释了几个与昆虫碎片在没有前胸腺的情况下蜕皮有关的异常观察，并提出了控制昆虫蜕皮和变态的复杂系统。
It is generally accepted that the prothoracic glands of insects produce ecdysone, which is converted by a 20-monooxygenase in peripheral tissues to the major molting hormone, 20-hydroxyecdysone. Incubation in vitro of the prothoracic glands of larval or pupal Manduca sexta in the presence of a hemolymph protein fraction (HPF) increased the ecdysteroid content of the medium almost 8-fold. A comparable increase was noted when HPF was added to medium preconditioned with prothoracic glands but from which the glands had been removed. We used a differential RIA to show that a major product of the prothoracic glands in vitro cross-reacts with antiserum (20-hydroxyecdysone-2-succinylthyroglobulin amide; H-2) that retains affinity to ecdysteroids having a modified A ring. However, this product did not bind to antiserum (ecdysone-22-succinylthyroglobulin amide; H-22) that has affinity mainly for ecdysteroids modified at the side chain. We employed radiolabeled precursor studies with prothoracic glands in vitro and a combination of analytical techniques (NMR, CD, MS) to demonstrate that the major ecdysteroid release from the glands is a mixture of 2-dehydroecdysone and 3-dehydroecdysone (1:2), which is rapidly reduced to ecdysone in the presence of HPF. We postulate that the active component of HPF is 3 beta 3 beta (2 beta)-formin-3(2)-ketoecdysteroid reductase. These results may explain several anomalous observations pertaining to the molting of insect fragments in the absence of prothoracic glands and suggest a complex system for the control of insect molting and metamorphosis.