Ecdysteroids: the overlooked sex steroids of insects? Males: the black box
Ecdysteroids: the overlooked sex steroids of insects? Males: the black box
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DOI：
10.1111/j.1744-7917.2006.00101.x
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发表时间：
2006-10-01
期刊：
影响因子：
4
通讯作者：
De Loof, Arnold
中科院分区：
文献类型：
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作者：
De Loof, Arnold
教科书中仍然存在的范例，即“昆虫的性别是严格遗传的，因此它们没有性别差异”，主要是基于对I型雌雄同体论点的错误解释。它不再站得住脚。鉴于脊椎动物和无脊椎动物可能有一个共同的有性生殖的祖先，没有理由认为只有脊椎动物需要性激素。性激素的主要功能是将性腺中发生的发育变化告知体质。与保幼激素和神经肽相反，蜕皮甾体符合性激素的所有标准，这可能是它们古老的作用。它们在蜕皮和变态中的作用是一种次级获得，使节肢动物能够科普由坚硬的角质层引起的生长问题。雌性昆虫使用由卵巢滤泡细胞分泌的20-羟基蜕皮酮（20 E），其方式与产卵脊椎动物的雌性使用雌激素类似。由于各种原因，蜕皮甾体，特别是蜕皮激素（E），也可能作为雄性昆虫的性激素，从而作为脊椎动物睾酮的对应物，一直被忽视。由于最近发现了蜜蜂性别决定的单倍体-二倍体系统的分子基础，万圣节基因的表征，蛋白质组学，RNAi等，现在有可能验证昆虫是否像脊椎动物一样，雄性是内分泌学默认的性别形式。
The paradigm, still around in textbooks, that 'in insects sex is strictly genetic, thus that they do not have sex hormones', is mainly based on a wrong interpretation of the I gynandromorph argument'. It is no longer tenable. Given the fact that vertebrates and invertebrates probably had a common, sexually reproducing ancestor, there is no reason to assume that only vertebrates need sex hormones. The major function of sex hormones is to inform the somatoplasm about developmental changes that take place in the gonads. In contrast to juvenile hormone and neuropeptides, ecdysteroids meet all criteria to act as sex hormones, which was probably their ancient role. Their much better documented role in moulting and metamorphosis was a secondary acquisition that enabled arthropods to cope with growth problems, imposed by a rigid cuticle. Female insects use 20-hydroxyecdysone (20E), secreted by the follicle cells of the ovary, in a similar way as females of egg-laying vertebrates use estrogens. For a variety of reasons, the possibility that ecdysteroids, in particular ecdysone (E), might also act as sex hormones in male insects, thus as the counterpart of testosterone of vertebrates, has been very much overlooked. Thanks to the recent discovery of the molecular basis of the haploid-diploid system of sex determination in the honeybee, the characterization of Halloween genes, proteomics, RNAi and so on, it now becomes possible to verify whether in insects, as with vertebrates, males are the endocritiologically default gender form.