Ishiwata K, Ido T, Imahori Y, Yamaguchi K, Fukuda H, Tada M, Matsuzawa T
Division of Radioisotope Research, Tohoku University, Sendai, Japan.
Int J Rad Appl Instrum B. 1988;15(3):271-6. doi: 10.1016/0883-2897(88)90106-7.
To investigate the highest accumulation of 2-deoxy-2-[18F]fluoro-D-galactose ([18F]FdGal) in the liver, metabolic studies with [18F]FdGal were carried out in Wistar rats for 120 min after i.v. injection. As main metabolites 2-deoxy-2-[18F]fluoro-D-galactose 1-phosphate ([18F]FdGal-1-P) and UDP-2-deoxy-2-[18F]-fluoro-D-galactose (UDP-[18F]FdGal) were identified in the liver and other tissues. The [18F]FdGal was phosphorylated by galactokinase. The phosphorylation rate was very rapid in the liver, in which at 5 min after injection 81% of 18F was detected as [18F]FdGal-1-P. After this time the phosphate form decreased with time, which was explained by conversion of [18F]FdGal-1-P to UDP-[18F]FdGal by UDP-glucose: galactose-1-phosphate uridyltransferase. At 120 min after injection 77% of the 18F was measured in the UDP-[18F]FdGal. In the brain both reaction rates were slower than in the liver. Both phosphate and uridylate derivates were also observed as main metabolites in the heart, lung, spleen and small intestine. On the other hand, a small amount of [18F]FdGal-1-P was detected in the plasma, in which the percentage of phosphate increased gradually and was 6% at 120 min. These results show that the [18F]FdGal metabolism in tissue results in phosphate and uridylate trapping and that the [18F]FdGal has potential for measuring in vivo galactose metabolism with positron emission tomography.
为研究2-脱氧-2-[¹⁸F]氟-D-半乳糖（[¹⁸F]FdGal）在肝脏中的最高蓄积情况，在静脉注射后对Wistar大鼠进行了120分钟的[¹⁸F]FdGal代谢研究。在肝脏和其他组织中鉴定出主要代谢产物2-脱氧-2-[¹⁸F]氟-D-半乳糖1-磷酸（[¹⁸F]FdGal-1-P）和UDP-2-脱氧-2-[¹⁸F]氟-D-半乳糖（UDP-[¹⁸F]FdGal）。[¹⁸F]FdGal被半乳糖激酶磷酸化。肝脏中的磷酸化速率非常快，注射后5分钟时，81%的¹⁸F被检测为[¹⁸F]FdGal-1-P。此后，磷酸形式随时间减少，这是由于UDP-葡萄糖：半乳糖-1-磷酸尿苷酰转移酶将[¹⁸F]FdGal-1-P转化为UDP-[¹⁸F]FdGal所致。注射后120分钟时，77%的¹⁸F在UDP-[¹⁸F]FdGal中被检测到。在大脑中，两种反应速率均比在肝脏中慢。在心脏、肺、脾脏和小肠中，磷酸和尿苷酸衍生物也被观察到是主要代谢产物。另一方面，在血浆中检测到少量的[¹⁸F]FdGal-1-P，其中磷酸的百分比逐渐增加，在120分钟时为6%。这些结果表明，组织中的[¹⁸F]FdGal代谢导致磷酸和尿苷酸捕获，并且[¹⁸F]FdGal具有利用正电子发射断层扫描测量体内半乳糖代谢的潜力。
