Sexual dimorphism arises from genetic differences between male and female cells, and from systemic hormonal differences1–3. How sex hormones affect non-reproductive organs is poorly understood, yet highly relevant to health given the sex-biased incidence of many diseases4. Here we report that steroid signalling in Drosophila from the ovaries to the gut promotes growth of the intestine specifically in mated females, and enhances their reproductive output. The active ovaries of the fly produce the steroid hormone ecdysone, which stimulates the division and expansion of intestinal stem cells in two distinct proliferative phases via the steroid receptors EcR and Usp and their downstream targets Broad, Eip75B and Hr3. Although ecdysone-dependent growth of the female gut augments fecundity, the more active and more numerous intestinal stem cells also increase female susceptibility to age-dependent gut dysplasia and tumorigenesis, thus potentially reducing lifespan. This work highlights the trade-offs in fitness traits that occur when inter-organ signalling alters stem-cell behaviour to optimize organ size. High levels of the sexually dimorphic hormone ecdysone, produced by active ovaries in Drosophila, promote the proliferation of stem cells in the female gut and maximize reproductive fitness, but also increase female susceptibility to age-dependent dysplasia and tumorigenesis.

中文翻译：

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果蝇中卵巢到肠道类固醇信号的适应性权衡

性别二态性源于男性和女性细胞之间的遗传差异，以及全身激素差异1-3。人们对性激素如何影响非生殖器官知之甚少，但鉴于许多疾病的发病率具有性别偏见，因此与健康高度相关4。在这里，我们报告了果蝇中从卵巢到肠道的类固醇信号传导，特别是在交配的雌性中促进了肠道的生长，并增强了它们的生殖输出。果蝇活跃的卵巢产生类固醇激素蜕皮激素，通过类固醇受体 EcR 和 Usp 及其下游靶标 Broad、Eip75B 和 Hr3，在两个不同的增殖阶段刺激肠道干细胞的分裂和扩张。尽管雌性肠道的蜕皮激素依赖性生长增强了生育能力，更活跃和更多的肠道干细胞也会增加女性对年龄依赖性肠道发育不良和肿瘤发生的易感性，从而可能缩短寿命。这项工作强调了当器官间信号传递改变干细胞行为以优化器官大小时发生的健康特征的权衡。果蝇活跃卵巢产生的高水平的性二态激素蜕皮激素可促进雌性肠道干细胞的增殖并最大限度地提高生殖健康，但也会增加雌性对年龄依赖性发育不良和肿瘤发生的易感性。