Rimar S, Gillis C N
Department of Anesthesiology, Yale University School of Medicine, New Haven, Connecticut 06510.
J Appl Physiol (1985). 1992 Aug;73(2):557-62. doi: 10.1152/jappl.1992.73.2.557.
Substantial removal of the vasoconstrictor peptide endothelin-1 (ET-1) by the pulmonary circulation has been reported to occur in perfused guinea pig and rat lungs. We examined the uptake of ET-1 by coronary and pulmonary circulations of the rabbit by measuring single-pass extraction of ET-1 in the isolated heart and lung. In separate experiments, each organ was perfused at 30 ml/min with Krebs-albumin (3%) solution. A bolus of 125I-ET-1 and [14C]dextran in 0.3 ml Krebs-albumin solution was injected, and extraction of endothelin (EET), relative to that of an intravascular reference indicator, [14C]dextran, was determined by multiple indicator-dilution technique. EET was 5 +/- 2% (SE) in the heart and 49 +/- 4% in the lung. Increasing flow rate in the lung preparation to approximate the mean transit time in the heart preparation did not significantly alter EET. Despite insignificant uptake of ET-1, the coronary circulation extracted an angiotensin-converting enzyme inhibitor (351A) and metabolized a synthetic angiotensin-converting enzyme substrate (benzoyl-phenyl-alanyl-proline), both properties of the normal pulmonary circulation. We therefore conclude that there is no significant ET-1 uptake in the coronary vascular bed.
据报道，在灌注的豚鼠和大鼠肺中，肺循环可大量清除血管收缩肽内皮素-1（ET-1）。我们通过测量离体心脏和肺中ET-1的单程提取率，研究了兔冠状动脉和肺循环对ET-1的摄取情况。在单独的实验中，每个器官均以30 ml/min的速度用Krebs-白蛋白（3%）溶液灌注。向0.3 ml Krebs-白蛋白溶液中注射125I-ET-1和[14C]葡聚糖的团注，通过多指示剂稀释技术测定相对于血管内参考指示剂[14C]葡聚糖的内皮素提取率（EET）。心脏的EET为5±2%（标准误），肺的EET为49±4%。将肺制备中的流速提高至接近心脏制备中的平均通过时间，并未显著改变EET。尽管ET-1的摄取不显著，但冠状动脉循环可提取一种血管紧张素转换酶抑制剂（351A）并代谢一种合成的血管紧张素转换酶底物（苯甲酰-苯丙氨酰-脯氨酸），这两种都是正常肺循环的特性。因此，我们得出结论，冠状动脉血管床中不存在显著的ET-1摄取。
