Department of Experimental and Clinical Pharmacology, Medical University of Lublin, Jaczewskiego 8B Str., 20-090 Lublin, Poland.
Department of Molecular Biology, The John Paul II Catholic University of Lublin, Konstantynow 1H, 20-708 Lublin, Poland.
Biomolecules. 2024 Sep 11;14(9):1148. doi: 10.3390/biom14091148.
Kynurenic acid (KYNA) is a metabolite of tryptophan formed on the kynurenine pathway. Its pharmacological effects are relatively well characterized in mammals, whereas its role in fish is poorly understood. Therefore, the aim of the study was to expand the knowledge of KYNA's presence inside a fish's body and its impact on fish development and function. The study was performed on zebrafish larvae and adult rainbow trout. We provide evidence that KYNA is present in the embryo, larva and mature fish and that its distribution in organs varies considerably. A study of KYNA's effect on early larval development suggests that it can accelerate larval maturation, especially under conditions that are suboptimal for fish growth. Moreover, KYNA in concentrations over 1 mM caused morphological impairment and death of larvae. However, long-lasting exposure of larvae to subtoxic concentrations of KYNA does not affect the behavior of 5-day-old larvae kept under standard optimal conditions. We also show that ingestion of KYNA-supplemented feed can lead to KYNA accumulation, particularly in the pyloric caeca of mature trout. These results shed new light on the relevance of KYNA and provide new impulse for further research on the importance of the kynurenine pathway in fish.
犬尿酸（KYNA）是色氨酸在犬尿氨酸途径中形成的一种代谢物。其在哺乳动物中的药理学作用已得到较好的描述，而在鱼类中的作用尚不清楚。因此，本研究旨在扩大对鱼类体内 KYNA 存在及其对鱼类发育和功能影响的认识。该研究在斑马鱼幼虫和成年虹鳟鱼上进行。我们提供的证据表明，KYNA 存在于胚胎、幼虫和成熟鱼体内，其在器官中的分布差异很大。对 KYNA 对早期幼虫发育影响的研究表明，它可以加速幼虫的成熟，特别是在鱼类生长的不利条件下。此外，浓度超过 1mM 的 KYNA 会导致幼虫形态损伤和死亡。然而，幼虫长期暴露于亚毒性浓度的 KYNA 不会影响在标准最佳条件下饲养的 5 日龄幼虫的行为。我们还表明，摄入添加 KYNA 的饲料会导致 KYNA 积累，特别是在成熟虹鳟鱼的幽门盲囊中。这些结果揭示了 KYNA 的相关性，并为进一步研究犬尿氨酸途径在鱼类中的重要性提供了新的动力。
