Landel A M, Lo C C, Meguid M M
Cancer. 1987 Mar 15;59(6):1192-200. doi: 10.1002/1097-0142(19870315)59:6<1192::aid-cncr2820590627>3.0.co;2-j.
Effects of tumor, operative stress and tumor removal, and postoperative TPN of varying amino acid compositions on brain levels of tryptophan or tyrosine as predicted by their brain influx rates were studied in normals and in malnourished cancer patients. Concentrations of the large neutral amino acids (LNAA) were determined in patients before and after tumor removal, and in postoperative patients before and after receiving either a standard TPN solution (STD-TPN), or a branched-chain amino acid solution (BCAA-TPN). The LNAA were altered in all groups versus normals. Brain influx rates showed the following: in preoperative patients, predicted brain tryptophan levels were below normal (P less than 0.001), whereas tyrosine levels were within or above normal; no significant differences between pre- and postoperative tryptophan or tyrosine levels; postoperative STD-TPN did not change predicted brain tryptophan concentration from preinfusion values, but BCAA-TPN decreased it (P less than 0.001), underscoring the common transport carrier; and preinfusion predicted brain tyrosine levels were decreased (P less than 0.001) by both types of TPN solutions. These results imply low substrate levels for brain serotonin and catecholamine synthesis, possibly affecting functions dependent on their control.
研究了肿瘤、手术应激与肿瘤切除，以及不同氨基酸组成的术后全胃肠外营养（TPN）对正常人和营养不良癌症患者脑中色氨酸或酪氨酸水平的影响（根据它们的脑内流入率预测）。在肿瘤切除前后的患者，以及接受标准TPN溶液（STD-TPN）或支链氨基酸溶液（BCAA-TPN）的术后患者中，测定了大中性氨基酸（LNAA）的浓度。与正常人相比，所有组的LNAA均发生了改变。脑内流入率显示如下：术前患者中，预测的脑色氨酸水平低于正常（P<0.001），而酪氨酸水平在正常范围内或高于正常；术前和术后色氨酸或酪氨酸水平之间无显著差异；术后STD-TPN未改变输注前预测的脑色氨酸浓度，但BCAA-TPN使其降低（P<0.001），突出了共同转运载体；两种TPN溶液均使输注前预测的脑酪氨酸水平降低（P<0.001）。这些结果表明，脑内血清素和儿茶酚胺合成的底物水平较低，可能会影响依赖于它们调控的功能。
