Weis M T, Palazzo A J, Williams J L, Malik K U
Department of Pharmacology, School of Medicine, University of Tennessee Center for the Health Sciences, Memphis 38163.
Lipids. 1990 Aug;25(8):497-503. doi: 10.1007/BF02538094.
The purpose of these experiments was to study the uptake and metabolism of exogenous triglyceride in the isolated perfused rabbit heart. When infused into the rabbit heart, [9,10-3H(N)]triolein was retained and incorporated into a lipid fraction that had the chromatographic mobility of authentic triolein. Incorporation of labeled triolein was not likely to be the result of a lipoprotein lipase-mediated lipolysis/resynthesis cycle, since: (i) The distribution of radioactivity following administration of [3H]oleic acid was markedly different from the distribution of radioactivity following the administration of [3H]triolein; (ii) heparin was administered to the rabbits at the time of sacrifice; and (iii) the hearts were perfused with a protein-free buffer for 20 min prior to the labelling period. When isoproterenol was administered to hearts labelled with [3H]triolein, there was an increased output of total radioactivity, composed of labelled free fatty acids, diacylglycerol and monoacylglycerol. In these same hearts, there was an increased output of glycerol in response to isoproterenol. However, following the administration of bradykinin or angiotensin II, neither the radioactivity nor the glycerol content of the perfusate was changed. These data suggest that [3H]triolein is selectively incorporated into the triglyceride pool of the isolated perfused rabbit heart. Furthermore, this [3H]triolein is available to hormonally-activated lipolytic enzymes.
这些实验的目的是研究外源性甘油三酯在离体灌注兔心脏中的摄取和代谢。当[9,10-³H(N)]三油酸甘油酯注入兔心脏时，它会被保留并掺入到具有真实三油酸甘油酯色谱迁移率的脂质部分中。标记的三油酸甘油酯的掺入不太可能是脂蛋白脂肪酶介导的脂解/再合成循环的结果，因为：(i)[³H]油酸给药后的放射性分布与[³H]三油酸甘油酯给药后的放射性分布明显不同；(ii)在处死兔子时给予肝素；(iii)在标记期之前，心脏用无蛋白缓冲液灌注20分钟。当向用[³H]三油酸甘油酯标记的心脏给予异丙肾上腺素时，由标记的游离脂肪酸、二酰甘油和单酰甘油组成的总放射性输出增加。在这些相同的心脏中，对异丙肾上腺素的反应是甘油输出增加。然而，在给予缓激肽或血管紧张素II后，灌注液的放射性和甘油含量均未改变。这些数据表明，[³H]三油酸甘油酯被选择性地掺入到离体灌注兔心脏的甘油三酯池中。此外，这种[³H]三油酸甘油酯可被激素激活的脂解酶利用。
