Nutritional regulation of hepatic glucose metabolism in fish
Nutritional regulation of hepatic glucose metabolism in fish
复制标题
DOI：
10.1007/s10695-008-9259-5
复制
发表时间：
2009-08-01
影响因子：
2.9
通讯作者：
Oliva-Teles, A.
中科院分区：
文献类型：
--
作者：
Enes, P.;Panserat, S.;Oliva-Teles, A.
葡萄糖在大多数哺乳动物中作为能量来源起着关键作用，但其在鱼类中的重要性似乎有限。到目前为止，鱼类这种明显的葡萄糖耐受不良的生理基础尚未完全了解。肝葡萄糖利用（糖酵解）和生产（糖原合成）的一个独特的调节可能是先进的，以解释鱼的相对不能有效地利用膳食葡萄糖。我们在这里总结了有关的营养调控的关键酶参与糖酵解（己糖激酶，6-磷酸果糖-1-激酶和丙酮酸激酶）和糖异生（磷酸烯醇丙酮酸羧激酶，果糖-1，6-二磷酸酶和葡萄糖-6-磷酸酶）途径，以及双功能酶6-磷酸果糖-2-激酶/果糖-2，6-二磷酸酶。本文还讨论了饲粮碳水化合物水平和来源对上述关键酶活性和基因表达的影响。总体而言，数据强烈表明，大多数鱼类的肝脏显然能够调节葡萄糖储存。内源性葡萄糖的持续高水平的产生独立于碳水化合物的摄入水平，可能导致外源性（饲料）葡萄糖和内源性葡萄糖之间的竞争作为能量来源，这可能解释了饲料中的碳水化合物利用率低的鱼类。
Glucose plays a key role as energy source in the majority of mammals, but its importance in fish appears limited. Until now, the physiological basis for such apparent glucose intolerance in fish has not been fully understood. A distinct regulation of hepatic glucose utilization (glycolysis) and production (gluconeogenesis) may be advanced to explain the relative inability of fish to efficiently utilize dietary glucose. We summarize here information regarding the nutritional regulation of key enzymes involved in glycolysis (hexokinases, 6-phosphofructo-1-kinase and pyruvate kinase) and gluconeogenesis (phosphoenolpyruvate carboxykinase, fructose-1,6-bisphosphatase and glucose-6-phosphatase) pathways as well as that of the bifunctional enzyme 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase. The effect of dietary carbohydrate level and source on the activities and gene expression of the mentioned key enzymes is also discussed. Overall, data strongly suggest that the liver of most fish species is apparently capable of regulating glucose storage. The persistent high level of endogenous glucose production independent of carbohydrate intake level may lead to a putative competition between exogenous (dietary) glucose and endogenous glucose as the source of energy, which may explain the poor dietary carbohydrate utilization in fish.