BLOOD AND TISSUE BRANCHED-CHAIN AMINO AND ALPHA-KETO ACID CONCENTRATIONS - EFFECT OF DIET, STARVATION, AND DISEASE
BLOOD AND TISSUE BRANCHED-CHAIN AMINO AND ALPHA-KETO ACID CONCENTRATIONS - EFFECT OF DIET, STARVATION, AND DISEASE
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DOI：
10.1093/ajcn/34.2.173
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发表时间：
1981-01-01
影响因子：
7.1
通讯作者：
HARPER, AE
中科院分区：
文献类型：
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作者：
HUTSON, SM;HARPER, AE
测量喂食低蛋白（8%酪蛋白）或高蛋白（60%酪蛋白）饮食的大鼠的血液、血浆和组织中的支链α-酮和氨基酸（BCKA、BCAA)浓度；以及在喂食库存饮食并遭受 3 天饥饿或化学诱导糖尿病的大鼠中。研究人员测量了枫糖浆尿病患者血液中这些氨基酸和酮酸的浓度。饲喂原粮的大鼠血液中缬氨酸、异亮氨酸和亮氨酸浓度为124.+-。 7, 58 .+-. 4 和 99 .+-。分别为5μM。喂食高蛋白饮食的大鼠和糖尿病大鼠的血液支链氨基酸浓度升高2至3倍；饥饿大鼠的血液中观察到小幅增加。血液中支链氨基酸浓度的变化与组织中的浓度变化平行，但饥饿大鼠除外，其中骨骼肌中游离支链氨基酸池的增加比例高于循环池。饲喂储备饲料的大鼠的平均血液 BCKA 浓度较低； 7.9.+-. 0.5, 7.1.+-. 0.4 和 12.4 .+-。 α-酮异戊酸、α-酮-β-甲基戊酸和α-酮异己酸分别为0.7μM。所有治疗均导致血液 BCKA 浓度增加 1.4 至 2 倍。除α-酮异己酸外，BCKA 的肝脏和心脏浓度接近检测限（< 1 nmol/g）。所有 3 种 BCKA 在骨骼肌中都有显着积累，估计含有 .apprx。所测体内 80% 的游离 BCKA 库。血液 BCKA 得到良好调节。仅在患有枫糖浆尿病的患者中，BCKA 的血浆浓度才是组织 BCAA 代谢改变的有用指标。骨骼肌中 BCKA 的氧化受到低 BCKA 脱氢酶活性的限制，可能是循环 BCKA 的主要来源。
Branched-chain .alpha.-keto and amino acid (BCKA, BCAA) concentrations were measured in blood, plasma and tissues of rats fed low protein (8% casein) or high protein (60% casein) diets; and in rats fed a stock diet and subjected to 3 days of starvation or chemically-induced diabetes. Concentrations of these amino and ketoacids were measured in blood from patients with maple syrup urine disease. Valine, isoleucine and leucine concentrations in blood from rats fed the stock diet were 124 .+-. 7, 58 .+-. 4 and 99 .+-. 5 .mu.M, respectively. Blood BCAA concentrations of rats fed the high protein diet and diabetic rats were elevated 2- to 3-fold; small increases were observed in blood from starved rats. Changes in blood BCAA concentrations paralleled those in tissues, except in starved rats in which the skeletal muscle free BCAA pool increased proportionately more than the circulating pool. Mean blood BCKA concentrations of rats fed the stock diet were low; 7.9 .+-. 0.5, 7.1 .+-. 0.4 and 12.4 .+-. 0.7 .mu.M for .alpha.-ketoisovaleric, .alpha.-keto-.beta.-methylvaleric and .alpha.-ketoisocaproic acids, respectively. All treatments resulted in increases in blood BCKA concentrations of from 1.4 to 2-fold. Liver and heart concentrations of BCKA, except for that of .alpha.-ketoisocaproic acid, were near the limits of detection (< 1 nmol/g). There was significant accumulation of all 3 BCKA in skeletal muscle which was estimated to contain .apprx. 80% of the measured body free BCKA pool. Blood BCKA are well regulated. Only in patients with maple syrup urine disease are plasma concentrations of BCKA useful indicators of altered tissue BCAA metabolism. Sketal muscle, where oxidation of the BCKA is limited by low BCKA dehydrogenase activity, is probably the major source of circulating BCKA.