Hydrogen isotope (δ²H) analysis has been routinely used as an ecological tracer for animal movement and migration, yet a biochemical understanding of how animals incorporate this element in the synthesis of tissues is poorly resolved. Here, we apply a new analytical tool, amino acid (AA) δ²H analysis, in a controlled setting to trace the influence of drinking water and dietary macromolecules on the hydrogen in muscle tissue. We varied the δ²H of drinking water and the proportions of dietary protein and carbohydrates with distinct hydrogen and carbon isotope compositions fed to house mice among nine treatments. Our results show that hydrogen in the non-essential (AA_NESS) and essential (AA_ESS) AAs of mouse muscle is not readily exchanged with body water, but rather patterns among these compounds can be described through consideration of the major biochemical pathway(s) used by organisms to synthesize or route them from available sources. Dietary carbohydrates contributed more hydrogen than drinking water to the synthesis of AA_NESS in muscle. While neither drinking water nor dietary carbohydrates directly contributed to muscle AA_ESS, we did find that a minor but measurable proportion (10–30%) of the AA_ESS in muscle was synthesized by the gut microbiome using hydrogen and carbon from dietary carbohydrates. δ²H patterns among individual AAs in mice muscle are similar to those we previously reported for bacteria, which provides additional support that this approach may allow for the simultaneous analysis of different AAs that are more influenced by drinking water (AA_NESS) versus dietary (AA_ESS) sources of hydrogen.

氢同位素（δ ² 2H）分析已经常规使用的作为生态示踪剂动物运动和迁移，但动物如何在组织中的合成将这一元件的生物化学理解甚少解决。在这里，我们应用一个新的分析工具，氨基酸（AA）δ ^2次ħ分析，以受控的设置，以跟踪对肌肉组织中的氢饮用水和膳食大分子的影响。我们改变了δ ²饮用水的H和饮食蛋白质的比例和碳水化合物与九种治疗馈送到家鼠不同氢和碳同位素组合物。我们的结果表明，氢气中的非必需（AA _NESS）和必需（AA _ESS）小鼠肌肉的AA不容易与人体水交换，而是可以通过考虑生物体从可用来源合成或路由它们的主要生化途径来描述这些化合物之间的模式。饮食中碳水化合物对肌肉中AA _NESS的合成贡献比饮用水更多的氢。尽管饮用水和饮食中的碳水化合物都没有直接导致肌肉AA _ESS，但我们确实发现，肠道微生物组利用饮食中的氢和碳合成了肌肉中少量但可测量的AA _ESS（10–30％）。δ ²小鼠肌肉中各个AA的H型与我们先前报道的细菌相似，这为我们提供了额外的支持，即该方法可以同时分析受饮用水（AA _NESS）与饮食（AA _ESS）影响更大的不同AA。）氢的来源。