Barle H, Nyberg B, Essén P, Andersson K, McNurlan M A, Wernerman J, Garlick P J
Department of Anesthesiology and Intensive Care, Huddinge University Hospital, Sweden.
Hepatology. 1997 Jan;25(1):154-8. doi: 10.1002/hep.510250128.
Although the metabolism of liver-derived plasma proteins such as albumin has been extensively studied, human hepatic protein synthesis as a whole has not been well characterized, because a reproducible model for obtaining human liver tissue has not been available. In this study, the fractional synthesis rates of total liver protein and albumin in vivo were determined simultaneously in nine subjects undergoing elective laparoscopic cholecystectomy. L-[2H5]phenylalanine (45 mg/kg body wt) was administered for 10 minutes intravenously. Blood samples were collected at regular intervals for 90 minutes and a liver biopsy specimen was taken at 35 +/- 7 minutes. The enrichments of plasma free phenylalanine, plasma albumin, and total liver protein were measured with gas chromatography mass spectrometry (GC-MS). The fractional synthesis rate (FSR) of total liver protein was 24.7 +/- 3.1 %/d (mean +/- SD), and that of albumin was 5.9 +/-1.2%/d. The amount of albumin synthesized per day (absolute synthesis rate, ASR) was 109 +/- 21 mg/kg body wt. No correlation between FSR of total liver protein and ASR of albumin was found. It is concluded that the technique of obtaining liver tissue specimens during laparoscopic surgery may serve as a human in vivo model to study total liver protein synthesis. The fractional synthesis rate of total liver proteins (stationary and exported), equals approximately 25% of the liver protein content daily. Within the range of values of this study, the absolute synthesis rate of albumin was not correlated to the fractional synthesis rate of total liver protein.
尽管诸如白蛋白等肝脏来源的血浆蛋白的代谢已得到广泛研究，但由于尚未获得用于获取人肝脏组织的可重复模型，整个人类肝脏蛋白质合成尚未得到充分表征。在本研究中，对9名接受择期腹腔镜胆囊切除术的受试者同时测定了体内肝脏总蛋白和白蛋白的分数合成率。静脉注射L-[2H5]苯丙氨酸（45mg/kg体重）10分钟。每隔一定时间采集血样90分钟，并在35±7分钟时采集肝脏活检标本。用气相色谱-质谱联用仪（GC-MS）测定血浆游离苯丙氨酸、血浆白蛋白和肝脏总蛋白的富集情况。肝脏总蛋白的分数合成率（FSR）为24.7±3.1%/天（平均值±标准差），白蛋白的分数合成率为5.9±1.2%/天。每天合成的白蛋白量（绝对合成率，ASR）为109±21mg/kg体重。未发现肝脏总蛋白的FSR与白蛋白的ASR之间存在相关性。得出结论，在腹腔镜手术期间获取肝脏组织标本的技术可作为研究肝脏总蛋白合成的人类体内模型。肝脏总蛋白（固定和输出）的分数合成率约等于肝脏蛋白含量每日的25%。在本研究的值范围内，白蛋白的绝对合成率与肝脏总蛋白的分数合成率无关。
