Pitt B R, Hammond G L, Gillis C N
J Appl Physiol Respir Environ Exerc Physiol. 1982 Apr;52(4):887-92. doi: 10.1152/jappl.1982.52.4.887.
Pulmonary removal of [3H]prostaglandin E1 ([3H]PGE1) was measured by double indicator-dilution techniques after bolus injections of indocyanine green and trace amounts of [3H]PGE1 before and after 1-3 h of total cardiopulmonary bypass (CPB) or 3 h of left-heart bypass (LHB) in 18 anesthetized dogs. Before bypass, pulmonary removal was 85.7 +/- 1.2% (means +/- SE, n = 18) and was unchanged on restoration of normal circulation after 1-2 h of CPB (80.6 +/- 1.8%, n = 7) or 3 h of LHB (87.4 +/- 1.6%, n = 4). However, on restoration of normal pulmonary arterial blood flow after 3 h of CPB, removal was significantly decreased to 74.5 +/- 2.2% (P less than 0.01, n = 7). Postbypass depression of [3H]PGE1 removal may explain our previous observations that intrabypass elevations in endogenous immunoreactive prostaglandin E in dogs were not entirely reversible on cessation of 3-4 h of CPB. Possible factors underlying depression of post-CPB pulmonary removal of [3H]PGE1 include: 1) local saturation of [3H]PGE1 removal secondary to intrapulmonary or intravascular release of prostaglandin E, 2) inhibition of prostaglandin dehydrogenase activity, or 3) damage to endothelial cell transport of [3H]PGE1 from the pulmonary microcirculation.
在18只麻醉犬中，在进行1 - 3小时的全心肺转流（CPB）或3小时的左心转流（LHB）之前和之后，通过双指示剂稀释技术测量推注吲哚菁绿和微量[³H]前列腺素E1（[³H]PGE1）后肺对[³H]PGE1的清除率。在转流前，肺清除率为85.7±1.2%（平均值±标准误，n = 18），在CPB 1 - 2小时（80.6±1.8%，n = 7）或LHB 3小时（87.4±I.6% , n = 4）后恢复正常循环时，清除率无变化。然而，在CPB 3小时后恢复正常肺动脉血流时，清除率显著降低至74.5±2.2%（P<0.01，n = 7）。转流后[³H]PGE1清除率降低可能解释了我们之前的观察结果，即犬在转流期间内源性免疫反应性前列腺素E升高在CPB 3 - 4小时停止后并未完全恢复正常。CPB后肺对[³H]PGE1清除率降低的潜在因素可能包括：1）肺内或血管内前列腺素E释放导致[³H]PGE清除的局部饱和；2）前列腺素脱氢酶活性的抑制；或3）肺微循环中[³H]PGE1内皮细胞转运受损。
