Abendschein D R, Fox K A, Ambos H D, Sobel B E, Bergmann S R
Cardiovascular Division, Washington University School of Medicine, St. Louis, MO 63110.
Int J Rad Appl Instrum B. 1987;14(6):579-85. doi: 10.1016/0883-2897(87)90029-8.
To assess the contributions of metabolism to CO2 and back-diffusion of nonmetabolized tracer to total clearance of beta-methyl[1-11C]heptadecanoic acid ([1-11C]BMHDA) from myocardium and its distribution into lipid pools, 10-15 mCi of [1-11C]BMHDA were rapidly infused into the circumflex coronary artery of seven open-chest dogs. Externally detected clearance of myocardial 11C-activity was protracted (t1/2 = 41 +/- 18 min) with over 50% of extracted tracer retained in tissue after 20 min. Efflux of extracted [1-11C]BMHDA between 5 and 20 min was comprised of both 11CO2 (16.5 +/- 15.2%) and nonmetabolized [11C]BMHDA (24.6 +/- 11.5%). At 20 min, 11C-activity in lipid was distributed primarily between triglyceride (47 +/- 16% of total) and phospholipid (39 +/- 17%) pools. Partial oxidation to 11CO2 and partitioning into more than one lipid pool are likely to hinder evaluation of fatty acid metabolism based on residue detection of [1-11C]BMHDA with tomography.
为评估代谢对二氧化碳的贡献以及未代谢示踪剂的反向扩散对β-甲基[1-¹¹C]十七烷酸（[1-¹¹C]BMHDA）从心肌的总清除率及其在脂质池中的分布的影响，将10 - 15毫居里的[1-¹¹C]BMHDA快速注入7只开胸犬的回旋冠状动脉。外部检测到的心肌¹¹C活性清除过程较为持久（半衰期t1/2 = 41 ± 18分钟），20分钟后超过50%的摄取示踪剂保留在组织中。5至20分钟内摄取的[1-¹¹C]BMHDA的流出包括¹¹CO2（16.5 ± 15.2%）和未代谢的[¹¹C]BMHDA（24.6 ± 11.5%）。在20分钟时，脂质中的¹¹C活性主要分布在甘油三酯（占总量的47 ± 16%）和磷脂（39 ± 17%）池中。部分氧化为¹¹CO2以及分配到多个脂质池中可能会阻碍基于断层扫描对[1-¹¹C]BMHDA残留检测来评估脂肪酸代谢。
