Caloric restriction increases gluconeogenic and transaminase enzyme activities in mouse liver
Caloric restriction increases gluconeogenic and transaminase enzyme activities in mouse liver
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DOI：
10.1016/s0531-5565(02)00202-4
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发表时间：
2003-03-01
影响因子：
3.9
通讯作者：
Weindruch, R
中科院分区：
文献类型：
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作者：
Hagopian, K;Ramsey, JJ;Weindruch, R
长期热量限制（CR）已被证明可延长实验室啮齿动物的最长寿命。我们研究了喂食对照饮食或热量限制饮食的老年和幼年小鼠肝脏中糖异生酶和转氨酶的活性。在最后一次预定喂食时间48小时后采集肝脏样本。与对照组相比，接受热量限制的老年小鼠丙酮酸羧化酶、磷酸烯醇式丙酮酸羧激酶、果糖 - 1,6 - 二磷酸酶和葡萄糖 - 6 - 磷酸酶的活性显著增加，表明糖异生作用增强。还观察到酪氨酸、色氨酸、组氨酸、苯丙氨酸、丙氨酸和天冬氨酸转氨酶以及苹果酸脱氢酶和谷氨酸脱氢酶的活性增加，而支链氨基酸转氨酶无变化。接受热量限制的幼年小鼠在糖异生途径中仅磷酸烯醇式丙酮酸羧激酶活性显著增加，而除色氨酸和支链氨基酸转氨酶外，转氨酶显著增加。谷氨酸脱氢酶活性也增加，但苹果酸脱氢酶无变化。仅在老年热量限制小鼠中观察到乙酰辅酶A水平和[乙酰辅酶A]/[辅酶A]比值增加。我们的结果表明热量限制小鼠的糖异生活性增加，且与热量限制期间肝脏糖异生和蛋白质周转增加的状态一致。(C) 2002爱思唯尔科学公司。保留所有权利。
Long-term caloric restriction (CR) has been shown to extend maximum life span in laboratory rodents. We investigated the activities of gluconeogenic and transaminase enzymes in the livers of old and young mice fed either control or calorie-restricted diets. Livers were sampled 48 h after the last scheduled feeding time. Old mice on CR showed significant increases in the activities of pyruvate carboxylase, phosphoenolpyruvate carboxykinase, fructose-1,6-bisphosphatase and glucose-6-phosphatase when compared with controls, indicating increased gluconeogenesis. Increased activities of tyrosine, tryptophan, histidine, phenylalanine, alanine and aspartate transaminases, as well as of malate and glutamate dehydrogenases were also observed, while branched-chain amino acid transaminase was unchanged. Young mice on CR showed a significant increase only in the phosphoenolpyruvate carboxykinase activity in the gluconeogenic pathway, while transaminases were increased significantly, except for tryptophan and branched-chain amino acid transaminases. Glutamate dehydrogenase also showed increased activity but malate dehydrogenase was unchanged. Increases in the level of acetyl-CoA and [Acetyl-CoA]/[CoA] ratio were observed only in the old CR mice. Our results demonstrate increased gluconeogenic activity in CR mice and are consistent with a state of increased hepatic gluconeogenesis and protein turnover during CR. (C) 2002 Elsevier Science Inc. All rights reserved.