The lack of an effective antioxidant system in beta-cells, which renders them susceptible to oxidative stress, is to date without explanation. The particular weakness of beta-cells in females, in both humans and mice, is another unexplained observation. We hypothesise that reactive oxygen species (ROS) in beta-cells, by their negative effect on insulin synthesis/secretion, play a fitness-enhancing role for the whole organism. Under stress conditions, the release of stress hormones produces insulin resistance and, owing to ROS preventing beta-cells from secreting insulin at the level required to maintain homeostasis, diverts glucose to insulin-independent tissues such as the brain and the foetus. We suggest that pancreatic beta-cells lost part of their antioxidant defence in association with brain evolution, and lost even more in females when placental mammals evolved. The unusual antioxidant status of beta-cells may thus be explained as an instance of co-evolution of the brain, cortisol and corticosteroid receptors, and beta-cells in the endocrine pancreas.

中文翻译：

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代谢进化为β细胞抗氧化防御的弱点提供了一种解释。

迄今为止，β 细胞缺乏有效的抗氧化系统，这使得它们容易受到氧化应激的影响。人类和小鼠中雌性 β 细胞的特殊弱点是另一个无法解释的观察结果。我们假设 β 细胞中的活性氧 (ROS) 通过它们对胰岛素合成/分泌的负面影响，对整个生物体起到增强健康的作用。在压力条件下，压力激素的释放会产生胰岛素抵抗，并且由于 ROS 阻止 β 细胞以维持体内平衡所需的水平分泌胰岛素，将葡萄糖转移到不依赖胰岛素​​的组织，如大脑和胎儿。我们认为，与大脑进化相关的胰腺β细胞失去了部分抗氧化防御能力，当胎盘哺乳动物进化时，雌性损失更多。因此，β 细胞异常的抗氧化状态可以解释为大脑、皮质醇和皮质类固醇受体以及内分泌胰腺中的 β 细胞共同进化的一个例子。