How vertebrates evolved different traits for acid excretion to maintain body fluid pH homeostasis is largely unknown. The evolution of Na⁺/H⁺ exchanger (NHE)‐mediated NH₄⁺ excretion in fishes is reported, and the coevolution with increased ammoniagenesis and accompanying gluconeogenesis is speculated to benefit vertebrates in terms of both internal homeostasis and energy metabolism response to acidic stress. The findings provide new insights into our understanding of the possible adaptation of fishes to progressing global environmental acidification. In human kidney, titratable H⁺ and NH₄⁺ comprise the two main components of net acid excretion. V‐type H⁺‐ATPase‐mediated H⁺ excretion may have developed in stenohaline lampreys when they initially invaded freshwater from marine habitats, but this trait is lost in most fishes. Instead, increased reliance on NHE‐mediated NH₄⁺ excretion is gradually developed and intensified during fish evolution. Further investigations on more species will be needed to support the hypothesis. Also see the video abstract here https://youtu.be/vZuObtfm-34.

中文翻译：

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脊椎动物的酸性应激抗性是否随着 Na+/H+ 交换剂介导的鱼类氨排泄而进化？

脊椎动物如何进化出不同的酸排泄特征以维持体液 pH 值稳态在很大程度上是未知的。据报道，Na ⁺ /H ⁺ 交换器（NHE）介导的 NH ₄ ⁺排泄在鱼类中的进化，推测与增加的氨生成和伴随的糖异生的共同进化在内部稳态和能量代谢对酸性应激的反应方面有益于脊椎动物. 这些发现为我们理解鱼类可能适应不断发展的全球环境酸化提供了新的见解。在人体肾脏中，可滴定的 H ⁺和 NH ₄ ⁺构成净酸排泄的两个主要成分。V型H ⁺当狭盐性七鳃鳗最初从海洋栖息地侵入淡水时，-ATPase 介导的 H ⁺排泄可能已经在它们中发展起来，但这种特性在大多数鱼类中消失了。相反，在鱼类进化过程中，对 NHE 介导的 NH ₄ ⁺排泄的依赖逐渐发展和加剧。需要对更多物种进行进一步调查来支持这一假设。另请参阅此处的视频摘要 https://youtu.be/vZuObtfm-34。