Moja E A, Rocchi E, Benedetti F, Paolillo F, Casalgrandi G, Ponz de Leon M
Chair of Psychobiology, Medical School, University of Modena, Italy.
Life Sci. 1991;48(5):409-18. doi: 10.1016/0024-3205(91)90496-x.
In healthy subjects the administration of an amino acid mixture devoid of tryptophan causes a marked decrease of plasma tryptophan. This is because amino acid mixtures induce protein synthesis and tryptophan in blood is incorporated into newly synthesized proteins. We hypothesized that a tryptophan-free mixture could differently affect plasma tryptophan levels in subjects with an impaired protein synthesis such as chronic liver patients. We studied tryptophan levels after a tryptophan-free amino acid solution in controls and cirrhotics fasting 12 hours. Plasma total tryptophan fell to 91% of the initial level 60 minutes after the administration of the diet, to 71% after 120, and to 50% after 210' in controls. In cirrhotics the solution caused a decrease of plasma tryptophan that began significantly later than in controls, the delay being proportional to the severity of the disease. Cirrhotics were subdivided into two groups in accordance to the Pugh modification of the Child-Turcotte criteria. Total plasma tryptophan was 100% of base line levels after 60', 88% after 120', and 65% after 210' in less severe clinical condition; total plasma tryptophan was 102% of base line levels after 60', 98% after 120', and 75% after 210' in more severe clinical condition.
在健康受试者中，给予不含色氨酸的氨基酸混合物会导致血浆色氨酸显著降低。这是因为氨基酸混合物会诱导蛋白质合成，血液中的色氨酸会被整合到新合成的蛋白质中。我们假设，不含色氨酸的混合物可能会对蛋白质合成受损的受试者（如慢性肝病患者）的血浆色氨酸水平产生不同影响。我们研究了在禁食12小时的对照组和肝硬化患者中，给予不含色氨酸的氨基酸溶液后的色氨酸水平。在对照组中，给予饮食后60分钟，血浆总色氨酸降至初始水平的91%，120分钟后降至71%，210分钟后降至50%。在肝硬化患者中，该溶液导致血浆色氨酸降低，其开始时间明显晚于对照组，延迟时间与疾病严重程度成正比。根据Child-Turcotte标准的Pugh修正版，将肝硬化患者分为两组。在病情较轻的情况下，60分钟后血浆总色氨酸为基线水平的100%，120分钟后为88%，210分钟后为65%；在病情较重的情况下，60分钟后血浆总色氨酸为基线水平的102%，120分钟后为98%，210分钟后为75%。
