Nutritional regulation and tissue specificity of gene expression for proteins involved in hepatic glucose metabolism in rainbow trout (Oncorhynchus mykiss).
Nutritional regulation and tissue specificity of gene expression for proteins involved in hepatic glucose metabolism in rainbow trout (Oncorhynchus mykiss).
复制标题
DOI：
--
复制
发表时间：
2001-07
期刊：
影响因子：
--
通讯作者：
S. Panserat;É. Plagnes-Juan;S. Kaushik
中科院分区：
文献类型：
--
作者：
S. Panserat;É. Plagnes-Juan;S. Kaushik
虹鳟鱼（Oncorhynchus mykiss）是众所周知的利用膳食碳水化合物差。解释这些鱼对膳食葡萄糖利用率低的假设之一是肝脏葡萄糖代谢的营养调节功能障碍。在这项研究中，我们获得了部分克隆虹鳟鱼cDNA编码的葡萄糖转运蛋白（Glut 2），和酶6-磷酸果糖-2-激酶/果糖-2，6-二磷酸酶（6PF-2K/F-2，6 BPase），果糖-1，6-二磷酸酶（FBPase）和丙酮酸激酶（PK）。它们推导的氨基酸序列与哺乳动物的氨基酸序列高度相似（高达80%的相似性）。在营养调节的研究中，Glut 2基因在肝脏中高度表达，与鳟鱼的营养状况无关，这与该转运蛋白在肝脏葡萄糖输入（再喂养期间）和输出（禁食期间）中的作用一致。此外，尽管PK和FBPase基因表达高，无论营养状况如何，肝脏6PF-2K/F-2，6 BPase mRNA水平在喂食碳水化合物的鱼中高于在剥夺食物的鱼中。在这项研究中观察到的肝脏PK，Glut 2和6PF-2K/F-2，6 BP酶基因表达水平高，表明虹鳟鱼组织碳水化合物利用的潜力很大。高水平的FBPase基因表达的持续性表明膳食碳水化合物对促炎途径的调节缺失。
Rainbow trout (Oncorhynchus mykiss) are known to use dietary carbohydrates poorly. One of the hypotheses to explain the poor utilisation of dietary glucose by these fish is a dysfunction in nutritional regulation of hepatic glucose metabolism. In this study, we obtained partial clones of rainbow trout cDNAs coding for a glucose transporter (Glut2), and for the enzymes 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase (6PF-2K/F-2,6BPase), fructose-1,6-bisphosphatase (FBPase) and pyruvate kinase (PK). Their deduced amino acid sequences were highly similar to those of mammals (up to 80% similarity). In a study of nutritional regulation, the Glut2 gene was highly expressed in the liver irrespective of the nutritional status of the trout, in agreement with the role of this transporter in the input (during refeeding) and output (during fasting) of glucose from the liver. Moreover, whereas PK and FBPase gene expression was high irrespective of the nutritional status, levels of hepatic 6PF-2K/F-2,6BPase mRNA were higher in fish fed with carbohydrates than in fish deprived of food. The high levels of hepatic PK, Glut2 and 6PF-2K/F-2,6BPase gene expression observed in this study suggest a high potential for tissue carbohydrate utilisation in rainbow trout. The persistence of a high level of FBPase gene expression suggests an absence of regulation of the gluconeogenic pathway by dietary carbohydrates.