Unidade de Investigação em Eco-Etologia, ISPA-Instituto Universitário, Lisbon, Portugal.
Zebrafish. 2013 Mar;10(1):110-5. doi: 10.1089/zeb.2012.0792. Epub 2013 Feb 27.
Zebrafish (Danio rerio) has recently emerged as a new animal model in neuroendocrinology and behavior (e.g., stress physiology and ecotoxicology studies). In these areas, the concentrations of steroid hormones in the blood are often used to study the endocrinological status of individuals. However, due to the small body size of zebrafish, blood sampling is difficult to perform and the amount of plasma obtained per sample for assaying hormones is very small (ca. 1-5 μL), and therefore most studies have been using whole-body hormone concentrations, which implies sacrificing the individuals and hampers sequential sampling of the same individual. Here a noninvasive method to assay steroid hormones from zebrafish holding-water, based on the fact that steroids are released into the fish holding-water through the gills by passive diffusion, is validated. Cortisol and the androgen 11-ketotestosterone (KT) were measured in water samples and compared to plasma levels in the same individuals. Cortisol released to holding-water correlates positively with plasma concentrations, but there was a lack of correlation between KT water and circulating levels. However, KT levels showed a highly significant sex difference that can be used to noninvasively sex individuals. An ACTH challenge test demonstrated that an induced increase in circulating cortisol concentration can be reliably detected in holding-water levels, hence attesting the responsiveness of holding-water levels to fluctuations in circulating levels.
斑马鱼（Danio rerio）最近已成为神经内分泌学和行为学（如应激生理学和生态毒理学研究）中的新型动物模型。在这些领域中，血液中类固醇激素的浓度常被用于研究个体的内分泌状态。然而，由于斑马鱼体型较小，采血较为困难，且每个样本用于测定激素的血浆量非常少（约 1-5 μL），因此大多数研究都采用了全身激素浓度，这意味着需要牺牲个体，并阻碍了对同一个体的连续采样。本研究基于类固醇通过鳃被动扩散释放到鱼类养殖水中这一事实，验证了一种从斑马鱼养殖水中测定类固醇激素的非侵入性方法。在水样中测定了皮质醇和雄激素 11-酮睾酮（KT），并与同一个体的血浆水平进行了比较。释放到养殖水中的皮质醇与血浆浓度呈正相关，但 KT 水与循环水平之间没有相关性。然而，KT 水平存在显著的性别差异，可用于非侵入性地鉴定个体性别。ACTH 挑战测试表明，循环皮质醇浓度的诱导增加可在养殖水中的水平可靠地检测到，从而证明养殖水中的水平对循环水平的波动具有反应性。
