Regional amino acid transport into brain during diabetes: effect of plasma amino acids.
Regional amino acid transport into brain during diabetes: effect of plasma amino acids.
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DOI：
10.1152/ajpendo.1987.253.5.e575
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发表时间：
1987-11
期刊：
影响因子：
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通讯作者：
A. Mans;M. DeJoseph;D. W. Davis;R. Hawkins
中科院分区：
文献类型：
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作者：
A. Mans;M. DeJoseph;D. W. Davis;R. Hawkins
测定链脲佐菌素糖尿病大鼠4周时苯丙氨酸和赖氨酸向脑内的转运，以评估其对血脑屏障中性和碱性氨基酸转运系统的影响。同时测定血浆和脑内氨基酸浓度。用连续输液法和定量放射自显影测定局部渗透倍表面积(PS)乘积和流入。在整个大脑中，苯丙氨酸的PS平均降低了40%。流入人口减少了35%。赖氨酸的PS平均增加44%，但内流减少27%。血浆中几种中性氨基酸(支链)增加，而所有碱性氨基酸减少。脑色氨酸、苯丙氨酸、酪氨酸、蛋氨酸和赖氨酸含量明显下降。转运的变化几乎完全是由于竞争中性和碱性氨基酸载体的血浆氨基酸浓度的变化。内流的减少可能是导致大脑中一些必需氨基酸含量较低的原因，可能会对大脑功能造成有害后果。
Transport of phenylalanine and lysine into the brain was measured in 4-wk streptozotocin-diabetic rats to assess the effect on the neutral and basic amino acid transport systems at the blood-brain barrier. Amino acid concentrations in plasma and brain were also measured. Regional permeability-times-surface area (PS) products and influx were determined using a continuous infusion method and quantitative autoradiography. The PS of phenylalanine was decreased by an average of 40% throughout the entire brain. Influx was depressed by 35%. The PS of lysine was increased by an average of 44%, but the influx was decreased by 27%. Several plasma neutral amino acids (branched chain) were increased, whereas all basic amino acids were decreased. Brain tryptophan, phenylalanine, tyrosine, methionine, and lysine contents were markedly decreased. The transport changes were almost entirely accounted for by the alterations in the concentrations of the plasma amino acids that compete for the neutral and basic amino acid carriers. The reduced influx could be responsible for the low brain content of some essential amino acids, with possibly deleterious consequences for brain function.