支链氨基酸对心肌缺血大鼠体内抗氧化系统的影响

用异丙肾上腺素（Ｉｓｏ）造成大鼠心肌缺血动物模型,观察支链氨基酸（ＢＣＡＡ）对大鼠心肌缺血损伤体内抗氧化系统及游离氨基酸的影响。结果表明,ＢＣＡＡ能明显降低体内的丙二醛（ＭＤＡ）水平,保护了体内谷胱甘肽过氧化物酶（ＧＳＨ－Ｐｘ）和超氧化物歧化酶（ＳＯＤ）的酶活力;并使心肌中谷氨酸、天冬氨酸水平显著升高,血清和心肌中丙氨酸水平显著提高。因此,给予ＢＣＡＡ对心脏缺血性损伤具有一定的防护效果。     

骨骼肌支链氨基酸代谢小分子与运动

骨骼肌是支链氨基酸的主要代谢场所,其代谢产生的分支α-酮酸,C3、C4和C5酰基肉碱,3-羟基异丁酸以及β-氨基异丁酸等代谢小分子,具有代谢和信号分子的双重身份,不仅作用于骨骼肌自身,还可进入血液循环,作用于脂肪、心肌、肝脏等外周组织,调节机体稳态。运动与支链氨基酸代谢关系密切,随着代谢组学的发展,运动与支链氨基酸代谢小分子的研究必将成为新的热点。本文将对上述支链氨基酸代谢小分子代谢过程、生物学功能及病理生理意义及运动对它们影响的研究进展进行综述。     

补服支链氨基酸对有氧运动耐力的影响

为了研究补服支链氨基酸(branched-chain amino acid,BCAA)对有氧运动耐力的影响,给白鼠补服BCAA,检测其对白鼠的运动能力和血清游离氨基酸代谢的影响;另选择健康男性作为受试者,于测试前30min分别口服氨基酸补剂及安慰剂,采取自身对照性分析法对比12min跑成绩及最大吸氧量的变化。结果表明,白鼠补充BCAA后,有氧运动的衰竭推迟出现,血清中BCAA的含量显著提高;人体数据研究表明,补服BCAA后,12min跑成绩和最大吸氧量均显著提高。表明补服BCAA能有效提高人体的有氧运动耐力。     

运动小鼠心肌和骨骼肌对支链氨基酸的摄取及其对蛋白质 …

目的和方法：本实验采用昆明种小鼠游泳运动模型,及＾１５Ｎ－Ｇｌｙｃｉｎｅ和＾３Ｈ－Ｌｅｕｃｉｎｅ同位素示踪技术探讨了运动状态下心肌和骨骼肌对ＢＣＡＡ的摄取量及ＢＣＡＡ对蛋白质合成的作用。结果：运动时心肌和骨骼肌从血循环中摄取ＢＣＡＡ显著增加,同时血清中ＢＣＡＡ的含量降低,结论：心肌和骨骼的蛋白质代谢存在差异,骨骼肌的蛋白质合成率高于心肌,运动使心肌蛋白代谢加速,补充ＢＣＡＡ降低了运动对心肌蛋白质代     

支链氨基酸的抗疲劳作用

支链氨基酸作为必需氨基酸,不仅是合成机体蛋白质的原料,而且具有特殊的生理、生物学功能。其代谢与抗疲劳作用的机理在本文中进行了详细阐述。     

支链氨基酸对心肌缺血大鼠线粒体损伤的保护作用

目的和方法：本文用异丙肾上腺素（Ｉｓｏ） 造成大鼠心肌缺血动物模型,观察支链氨基酸（ＢＣＡＡ）对大鼠心肌缺血时线粒体结构和功能损伤的预防作用。结果：ＢＣＡＡ 能显著降低心肌缺血后心肌线粒体中丙二醛（ＭＤＡ） 水平、维持线粒体模平均微粘度（－η） 、线粒体呼吸链中细胞色素氧化酶及心肌肌球蛋白ＡＴＰａｓｅ活力。结论：给予ＢＣＡＡ对保护大鼠心肌线粒体的结构和功能免受缺血性损伤具有一定效果     

支链氨基酸代谢及其与疾病的关系

亮氨酸、异亮氨酸和缬氨酸的疏水侧链都具有分支的甲基基团,因而被统称为支链氨基酸(branched chain amino acids, BCAAs)。作为机体的必需氨基酸,除了作为蛋白质合成的基本原料,BCAAs及其各种分解代谢产物还可以作为信号分子,调控从蛋白质合成到胰岛素分泌等众多生理过程。因此,它们的正常代谢对机体生命活动至关重要。越来越多的证据表明,BCAAs代谢异常与多种疾病关系密切,包括枫糖尿病、神经系统疾病、糖尿病、心血管疾病、肝疾病和癌症等。本文详细概述了哺乳动物中BCAAs分解代谢的基本模式、调控机制(主要关注对2个关键代谢酶BCAT和BCKDH的调控)以及BCAAs参与mTOR和AMPK信号通路在机体代谢中发挥的作用。总结了BCAAs代谢异常与多种疾病的关系,并对有关的矛盾观点进行阐述和解释。近年来,BCAAs代谢及调控在疾病发生发展中的作用成为研究热点,为相关疾病预防和治疗提供了新视角。本综述将为进一步研究提供线索。     

补充支链氨基酸对睡眠剥夺大鼠行为和血清游离脂肪酸水平的影响

探讨补充支链氨基酸 (branched -chainaminoacids ,BCAA)对睡眠剥夺 (sleepdeprivation ,SD)大鼠的行为和血清游离脂肪酸 (freefattyacids,FFA)水平的影响。采用小站台水环境 (flower -pot)睡眠剥夺模型对大鼠进行睡眠剥夺。成年、雄性Sprague-Dawley大鼠 5 6只 ,按体重随机分为C(对照组、自由睡眠 )、2 4hSD(剥夺睡眠 2 4h)、2 4hSDB(睡眠剥夺 2 4h ,进食添加BCAA的饲料 )、4 8hSD、4 8hSDB、72hSD、72hSDB组 ,每组 8只。睡眠剥夺结束后 ,采用旷场实验 (openfieldtest,OPT)评价大鼠的精神行为。结果各睡眠剥夺组大鼠的OFT得分均显著高于对照组 (P <0 .0 5 ) ;其中以 4 8hSD组最高 ,72hSD组的OFT得分又显著低于 72hSDB组 (P <0 .0 5 )。睡眠剥夺各组大鼠血清FFA水平均显著高于非剥夺组 ,72hSDB组显著高于 72hSD组 (P <0 .0 5 )。结论为补充支链氨基酸可以改善睡眠剥夺大鼠的旷场实验行为 ,降低睡眠剥夺大鼠血清FFA水平。     

复方高支链氨基酸对肝硬化大鼠肝功能及营养状况的影响

将SD雄性大鼠用四氯化碳处理建立肝硬化大鼠模型,并随机分为A、B、C三组,A组大鼠给予静脉输注生理盐水,B组、C组大鼠分别给予输注等量的普通氨基酸注射液和复方高支链氨基酸注射液,分别于实验第0d、第14d测定大鼠体质量、肝功能指标及营养学指标水平。实验结束后,B、C两组大鼠体质量明显增加,与A组相比,B、C两组大鼠肝功能各指标水平显著降低,血清蛋白水平显著升高,且C组相比,B组大鼠肝功能水平与血清蛋白水平改善作用更为明显(p<0.05)。说明复方高支链氨基酸能改善肝硬化大鼠的肝功能指标,抑制血浆蛋白分解,有效控制肝硬化病症的进一步恶化。     

富含谷氨酰胺和支链氨基酸的肠外制剂对创伤大鼠的效用

研究普通氨基酸注射液 (17AA)与富含谷氨酰胺及支链氨基酸注射液 (2 0AA)对创伤大鼠的营养效用。以Wistar大鼠为创伤模型 ,分别输注两种配方的氨基酸注射液 ,以日立L - 85 0 0氨基酸自动分析仪测定动物血浆游离氨基酸 ,并测定创伤处海绵内羟脯氨酸含量。结果显示创伤后大鼠血浆牛磺酸、谷氨酸、谷氨酰胺和支链氨基酸含量较术前下降 ,但 2 0AA组血浆氨基酸恢复优于 17AA组 ,创伤处海绵内羟脯氨酸含量 2 0AA组显著高于 17AA组 (1.2 9± 0 .2 1vs 0 .83± 0 .16mg/块海绵 ,P <0 .0 5 )。提示 ,创伤后给予富含谷氨酰胺和支链氨基酸的营养制剂能提高血浆氨基酸浓度并有利于创伤的恢复     

Neuronal Metabolism of Branched-Chain Amino Acids: Flux Through the Aminotransferase Pathway in Synaptosomes

Abstract: The metabolism of branched-chain amino acids (BCAAs) was studied in cortical synaptosomes. With [¹⁵N]leucine (1 mM) as precursor, the cumulative appearance of ¹⁵N in [¹⁵N]glutamate and [¹⁵N]aspartate was 0.2 nmol/min/mg of protein without supplemental α-ketoglutarate and 0.3 nmol/min/mg of protein in the presence of α-ketoglutarate (0.5 mM). The BCAA aminotransferase reaction also proceeded in the “reverse” direction [α-ketoisocaproate (KIC) + glutamate → leucine + α-ketoglutarate]. This was documented by incubating synaptosomes with [¹⁵N]glutamate and measuring the formation of [¹⁵N]leucine. Without KIC in the medium, the rate of [¹⁵N]leucine production was 0.13 nmol/min/mg of protein. In the presence of 25 µM KIC the rate was 0.79 nmol/min/mg of protein and even greater (1.0 nmol/min/mg of protein) in the presence of 500 µM KIC. The reamination of KIC was two- to threefold faster with [2-¹⁵N]glutamine as precursor compared with [¹⁵N]glutamate. The ketoacid of valine, α-ketoisovalerate (KIV), was reaminated to [¹⁵N]valine at a rate comparable to that observed with respect to KIC. The BCAA transaminase mediated not only the bidirectional transfer of amino groups between leucine or valine and glutamate, but also the direct transfer of nitrogen between leucine and valine. This was ascertained in studies in which the incubation medium was supplemented with either [¹⁵N]leucine and KIV or [¹⁵N]valine and KIC (amino acids at 1 mM and ketoacids at 25 or 500 µM). The rate was faster in the direction of leucine formation at both the lower (6.1-fold) and higher (1.7-fold) KIC concentration. It is suggested that in synaptosomes the BCAA transaminase (a) functions predominantly in the direction of leucine formation and (b) maintains a constant ratio of BCAAs and ketoacids to one other.     

多胺和氨基酸与儿童智能发育的研究

采用丹酰氯聚酰胺薄层分析法研究了３７名３～７岁健康儿童的红细胞多胺和血浆游离氨基酸,并采用“韦克斯勒学前儿童智力检查法”测试智能。结果表明：（１）红细胞多胺含量与学前儿童的大脑生长发育无明显影响,而支链氨基酸及苯丙氨酸、酪氨酸与大脑的功能活动及代谢有一定的作用。     

肝硬化疾病与支链氨基酸应用研究进展

蛋白质-营养不良是肝硬化病人最常见的并发症之一。肝脏作为蛋白质、脂类和糖代谢的主要器官,病变后的代谢紊乱随之而来。不适宜的蛋白质-能量摄入只会加重病情最后发生肝性脑病等危及生命的严重后果。因此,肝硬化病人的营养管理显得尤为重要,氨基酸的适宜供给无疑是营养治疗的重中之重。已知支链氨基酸能通过刺激肝细胞合成、减少肝损伤后的分解代谢等诸多方式改善营养状况,但是各种试验结果仍存在争议。最佳适宜量究竟多大,安全性范围的设定以及确切的保护机理等问题仍待进一步深入研究。     

Failure of Glucose and Branched-Chain Amino Acids to Normalize Brain Glucose Use in Portacaval Shunted Rats

Several abnormalities in brain and plasma amino acid concentrations caused by portacaval shunting in rats return toward normal after 4 days of intravenous infusion with either glucose or glucose with branched-chain amino acids. To assess the effect of such treatment on brain energy metabolism, regional brain glucose use was measured using [14C]glucose and autoradiography, 5 weeks after portacaval shunting. In one experiment intravenous glucose or glucose with branched-chain amino acids was given for 4 days. In a separate experiment the treatment was given orally for 2 weeks, and in addition to glucose use, brain monoamines and amino acids were measured. No other food was provided; the rats had free access to water. Normally fed shunted rats and sham-operated rats served as controls. Both types of oral treatment lowered the high concentrations of tyrosine, phenylalanine, and glutamine in plasma and brain. Glucose without amino acids normalized brain tryptophan. Levels of brain norepinephrine, 5-hydroxytryptamine (serotonin), and 5-hydroxyindoleacetic acid were significantly raised after shunting. Treatment had no effect on norepinephrine but the glucose diet brought the indoles into the normal range. In contrast, neither intravenous nor oral treatment affected brain glucose use, which remained depressed by 25-30% in all brain areas examined.     

烧伤患者血浆和红细胞游离氨基酸变化及输注氨基酸对其变化的影响

动态测定烧伤患者血浆及红细胞内游离氨基酸的含量 ,探讨输入外源性氨基酸后对血及红细胞内游离氨基酸的影响。以日立 835— 5 0型氨基酸自动分析仪测定烧伤患者血浆及红细胞内游离氨基酸含量。结果发现烧伤患者血浆总游离氨基酸浓度从伤后到 2 1天均显著降低 (P <0 .0 5～ 0 .0 1) ;赖、苯丙和苯丙 酪氨酸比值显著升高 (P <0 .0 5～ 0 .0 1) ;色、组、精、丙、甘、苏、脯和丝氨酸比值显著降低 (P <0 .0 5～ 0 .0 1) ;缬、亮、异亮、酪、胱和支链氨基酸伤后早期降低。烧伤患者红细胞内总游离氨基酸含量不同程度降低 ,其中 1、3、7天降低显著 (P <0 .0 5～ 0 .0 1) ;红细胞内苯丙和苯丙 酪氨酸比值未见显著性升高 ;色、蛋、精、脯氨酸含量很低或基本未测出。输注复合氨基酸注射液后未能显著改善患者血及红细胞内游离氨基酸含量。结果提示烧伤患者红细胞内游离氨基酸含量的变化趋势与血浆游离氨基酸变化趋势基本一致 ;烧伤后红细胞内苯丙氨酸及苯丙 酪氨酸比值有别于血浆变化。本研究条件下补充外源性氨基酸未能显著改变烧伤患者血浆及红细胞内游离氨基酸的含量     

利用液相色谱研究烘焙条件对白肋烟中游离氨基酸的影响

利用OPA、FMOC联合在线衍生反相高效液相色谱法测定白肋烟在110℃、120℃、130℃、140℃、150℃分别烘焙12m in和16 m in后游离氨基酸的含量,研究烘焙温度和烘焙时间对白肋烟中游离氨基酸的影响。结果显示整个烘焙过程是蛋白质的降解和M ailard反应相结合的动态过程,蛋白质的降解主要发生在110℃~120℃的低温区;而M ailard反应主要发生在130℃~150℃高温区。实验结果还表明烘焙时间对白肋烟在烘焙后游离氨基酸的含量有重要影响,烘焙时间的延长使烟叶中的游离氨基酸均有较大幅度降低,其中影响最明显的是Pro、Asp和Asn。     

Effects of Dietary Amino Acids on Brain Amino Acids and Transmitter Amines in Rats with a Portacaval Shunt

The etiologic relationship between disturbances in metabolism of amino acids and amines and hepatic coma was investigated by examining the effects of diets containing various mixtures of amino acids on brain amine metabolism in rats with a portacaval shunt, using a method for simultaneous analysis of amino acids and amines. Rats with a portacaval shunt were fed on four different amino acid compositions with increased amounts of various amino acids suspected to be etiologically related to hepatic coma, such as methionine, phenylalanine, tyrosine, and tryptophan. The animals were killed 4 weeks after operation. During the experimental period, these animals did not become comatose, but exhibited various behavioral abnormalities. Marked increase in the plasma and brain levels of the augmented amino acids, especially methionine and tyrosine, were observed in rats with a portacaval shunt. Brain noradrenaline, dopamine, and serotonin levels were significantly decreased when the brain tyrosine level was increased. These results indicate that in rats with a portacaval shunt the dietary levels of amino acids greatly influence the brain levels of both amino acids and transmitter amines.