Feinendegen L E, Herzog H, Wieler H, Patton D D, Schmid A
J Nucl Med. 1986 Dec;27(12):1867-77.
3-0-[11C]-Methyl-D-glucose (CMG) is specifically suited for measuring carrier facilitated glucose (G) transport; it enters the free G pool in tissue from where it is not utilized for metabolism in contrast to G, but is transported back into circulation. The ratio of carrier affinity for G and CMG was reported to be 1.11. By simultaneously measuring CMG concentration in plasma and in cerebral cortex in vivo with positron tomography at 1-min intervals for 40 min, two time-activity curves are obtained, as reported previously, which together with the G concentration in plasma yield the in vivo rate constants of G transport across the blood-brain barrier and the rate of G inflow; a repeat measurement at a different G concentration in plasma gives the in vivo Michaelis-Menten constant KM and the maximal rate of transport VMAX. The present paper summarizes and extends this approach to analyzing the free G pool in tissue, the rate of G return to circulation, and the rate of G exit into metabolism with its corresponding rate constants. The data from six volunteers agreed with results reported for the individual biochemical parameters in primate brains.
3-0-[11C]-甲基-D-葡萄糖（CMG）特别适合于测量载体介导的葡萄糖（G）转运；它进入组织中的游离G池，与G不同，它不会在那里用于代谢，而是被转运回循环系统。据报道，载体对G和CMG的亲和力之比为1.11。如先前报道的那样，通过在40分钟内每隔1分钟用正电子断层扫描同时测量体内血浆和大脑皮质中的CMG浓度，可获得两条时间-活性曲线，这些曲线与血浆中的G浓度一起得出G跨血脑屏障转运的体内速率常数和G流入速率；在血浆中不同G浓度下重复测量可得出体内米氏常数KM和最大转运速率VMAX。本文总结并扩展了这种方法，以分析组织中的游离G池、G返回循环系统的速率以及G进入代谢的速率及其相应的速率常数。来自六名志愿者的数据与灵长类动物大脑中各个生化参数的报道结果一致。
