热量限制对大鼠血清支链氨基酸、芳香族氨基酸、甘氨酸水平的影响及意义

摘要

目的：观察热量限制（CR）对大鼠血清支链氨基酸[缬氨酸（Val）、异亮氨酸（Ile）、亮氨酸（Leu）]、芳香族氨基酸[酪氨酸（ Tyr ）、苯丙氨酸（ Phe ）]及甘氨酸（ Gly ）水平的影响，并探讨其与胰岛素敏感性的关系。方法将20只雄性SD大鼠随机分为观察组和对照组各10只，对照组给予自由饮食，观察组限制热量摄入为对照组的60％。喂饲12周后称取两组体质量及附睾旁脂肪垫质量；行胰岛素耐量试验，绘制血糖值曲线并计算曲线下面积。采用液相色谱串联质谱法检测两组血清Val、Ile、Leu、Tyr、Phe及Gly。结果观察组体质量、附睾旁脂肪垫质量均低于对照组，P均＜0．01。观察组血糖值曲线下面积为728．1±65．7，对照组为955．1±39．0，P＜0．01。观察组血清Ile、Leu、Tyr水平均低于对照组，Gly水平高于对照组，P均＜0．05。两组血清Val、Phe水平比较，P均＞0．05。结论 CR可能通过升高大鼠血清Gly水平，降低Ile、Leu、Tyr水平而提高其胰岛素敏感性。%Objective To observe the effects of caloric restriction ( CR ) on levels of serum branched chain amino acids [ valine ( Val ) , isoleucine ( Ile ) , leucine ( Leu ) ] , aromatic amino acids [ tyrosine ( Tyr ) and phenylalanine (Phe)] and glycine of rats, and to investigate their relationships with insulin sensitivity .Methods Twenty male SD rats were randomly divided into the control group which was fed ad libitum and the observation group which was fed 60%of the food as in the control group.After 12 weeks, body weight was measured and insulin tolerance test (ITT) was performed. Blood glucose value curve was drawn and wevcalculated the area under the curve ( AUC).The levels of Val, Ile, Leu, Tyr, Phe and Gly were determined by liquid chromatography-tandem mass spectrometry .Results Both body weight and epididymal fat pad weight were lower in the observation group than in the control group (all P<0.01).AUC of blood glu-cose in the observation group was 728.1 ±65.7, and 955.1 ±39.0 in the control group, respectively (P<0.01).The se-rum concentrations of Ile , Leu and Tyr in the observation group were lower than those of the control group , and the concen-tration of Gly was higher (all P<0.05).No significant difference was found in the serum levels of Val and Phe between the two groups (all P>0.05).Conclusion CR increases the serum level of Gly , reduces the levels of Ile, Leu and Tyr, and thus it increases the insulin sensitivity .