Data from: The level of an intracellular antioxidant during development determines the adult phenotype in a bird species: a potential organizer role for glutathione

Life-history traits are often involved in trade-offs whose outcome would depend on the availability of resources but also on the state of specific molecular signals. Early conditions can influence trade-offs and program the phenotype throughout the lifetime, with oxidative stress likely involved in many taxa. Here we address the potential regulatory role of a single intracellular antioxidant in life-history trade-offs. Blood glutathione levels were reduced in a large sample of birds (zebra finch Taeniopygia guttata) during development using the synthesis inhibitor buthionine sulfoximine (BSO). Results revealed several modifications in the adult phenotype. BSO-treated nestlings showed lower glutathione and plasma antioxidant levels. In adulthood, BSO birds endured greater oxidative damage in erythrocytes but stronger expression of a sexual signal. Moreover, adult BSO females also showed weaker resistance to oxidative stress but were heavier and showed better body condition. Results suggest that low glutathione values during growth favor the investment in traits that should improve fitness returns, probably in the form of early reproduction. Higher oxidative stress in adulthood may be endured if this cost is paid later in life. Either the presence of specific signaling mechanisms or the indirect effect of increased oxidative stress can explain our findings.

生活史性状（life-history traits）往往涉及权衡（trade-off）关系，其结局不仅取决于资源可获得性，还受特定分子信号的状态影响。早期发育条件能够影响此类权衡，并在个体整个生命周期中塑造表型，而氧化应激在众多生物类群中均可能参与这一过程。本研究旨在探究单一细胞内抗氧化剂在生活史性状权衡中的潜在调控作用。

研究以大量斑胸草雀（zebra finch，*Taeniopygia guttata*）为实验对象，在其发育阶段使用合成抑制剂丁硫氨酸-亚砜亚胺（buthionine sulfoximine，BSO）降低其血液谷胱甘肽水平。实验结果显示，成体个体的表型出现多项显著改变：经BSO处理的雏鸟，其体内谷胱甘肽与血浆抗氧化水平均显著降低；至成体阶段，BSO处理组鸟类的红细胞氧化损伤程度更高，但性信号的表达强度更强。此外，BSO处理组的成年雌性个体，其氧化应激抵抗能力更弱，但体重更高、身体状况更佳。

研究结果表明，发育阶段的低谷胱甘肽水平，有利于个体将资源投入到可提升适合度回报的性状中，这或许表现为提前繁殖的生活史策略。若此类适合度代价在生命后期才显现，则成体阶段可承受更高程度的氧化应激。本研究结果可通过特定信号调控机制的存在，或是氧化应激水平升高带来的间接效应得到合理解释。