Xia Zhaofan, Tian Jianguang, Wang Guangyi, Ge Shengde, Tang Hongtai
Department of Burns Surgery, Changhai Hospital, Shanghai 200433, China.
Chin J Traumatol. 2002 Apr;5(2):71-6.
To introduce a safe and specific approach of (13)C magnetic resonance spectrum ((13)C MRS) spectroscopy and investigate the alterations in hepatic anabolism.
Relative anaplerotic, pyruvate recycling and gluconeogenic fluxes were measured by (13)C MRS isotopomer analysis of blood glucose from rats with 40% body surface area burn injury, and from rats exposed to sham injury. A short chain fatty acid, [U (13)C] propionate which was avidly extracted by the liver, was infused intravenously to deliver (13)C into the citric acid cycle. Proton-decoupled (13)C MRS of deproteinized plasma or extracts of the freeze-clamped liver were used to determine the distribution of (13)C in blood or hepatic glucose.
There was no difference in the multiplets detected in the glucose carbon-2 anomer from blood or liver after 45 or 60 minutes of the infusion of the propionate, indicating that steady-state isotopic conditions were achieved. Gluconeogenesis relative to citric acid cycle flux was not altered by burn injury; in both sham and burn groups the rate of glucose production was about equal to flux through citrate synthase. In the sham group of animals, the rate of entry of carbon skeletons into the citric acid cycle was about 4 times than that in the burn group. Similarly, flux through pyruvate kinase (again relative to citrate synthase) was significantly increased after the burn injury.
Since results from analysis of the blood glucose are the same as that of the hepatic glucose, (13)C distribution in the glucose and hepatic metabolism can be assessed based on the (13)C MRS analysis of the blood glucose.
介绍一种安全且特异的（13）C磁共振波谱（（13）C MRS）方法，并研究肝脏合成代谢的变化。
通过对40%体表面积烧伤大鼠及假伤大鼠的血糖进行（13）C MRS同位素异构体分析，测量相对的回补、丙酮酸循环和糖异生通量。静脉输注一种能被肝脏 avidly摄取的短链脂肪酸[U（13）C]丙酸盐，将（13）C输送到柠檬酸循环中。利用去蛋白血浆或冷冻钳夹肝脏提取物的质子去耦（13）C MRS来确定（13）C在血液或肝脏葡萄糖中的分布。
输注丙酸盐45或60分钟后，血液或肝脏中葡萄糖碳-2异头物检测到的多重峰无差异，表明达到了稳态同位素条件。烧伤并未改变相对于柠檬酸循环通量的糖异生；在假伤组和烧伤组中，葡萄糖生成速率均约等于通过柠檬酸合酶的通量。在假伤组动物中（13）C骨架进入柠檬酸循环的速率约为烧伤组的4倍。同样，烧伤后通过丙酮酸激酶的通量（同样相对于柠檬酸合酶）显著增加。
由于血糖分析结果与肝脏葡萄糖分析结果相同，因此可基于血糖的（13）C MRS分析评估葡萄糖中的（13）C分布及肝脏代谢情况。
