Turrin M Q, Gillis C N
Departamento de Farmacologia, Universidade de São Paulo, Brasil.
Braz J Med Biol Res. 1987;20(6):811-5.
The finding that radioiodinated, synthetic ANP (125I-ANP), analogous to the ANP secreted by the right atrium, binds to specific sites of endothelial cells, smooth muscle, adrenals and lungs (1-3) raised the importance of analyzing lung-ANP interactions. Rabbit lungs were accordingly loaded with 125I-ANP, 2000 Ci/mM (2.5 pM) in Krebs-albumin recirculating perfusion medium at a rate of 20 ml/min, over 27 min. 125I-ANP binding was estimated by taking samples at 2-min intervals from the perfusate. Fourteen min after recirculation, uptake was maximal (66.4 +/- 5.2%, N = 8) (X +/- SEM) and not different from that observed after a single passage through the lungs and was dose-dependent, antagonized by unlabelled ANP. The system was then changed to single-pass washout and efflux curves were obtained, collecting the entire efflux every 6 s per sample, over 15 min. Efflux curves after 125I-ANP loading fitted a bi-exponential decay model (Y(to) = Y(t)e-b11t + Y(t)e-b2t). Lung ANP uptake/release may be involved in regulating systemic concentrations and hence renal and other actions of ANP.
放射性碘化的合成心钠素（125I-ANP）与右心房分泌的心钠素类似，能与内皮细胞、平滑肌、肾上腺和肺的特定部位结合（1-3），这一发现凸显了分析肺-心钠素相互作用的重要性。因此，在27分钟内，以20毫升/分钟的速率，将2000居里/毫摩尔（2.5皮摩尔）的125I-ANP加载到处于Krebs-白蛋白循环灌注培养基中的兔肺中。通过每隔2分钟从灌注液中取样来估算125I-ANP的结合情况。再循环14分钟后，摄取量达到最大值（66.4±5.2%，N = 8）（X±SEM），与单次通过肺后观察到的摄取量无差异，且呈剂量依赖性，可被未标记的心钠素拮抗。然后将系统改为单次通过洗脱，并获得流出曲线，每个样本每6秒收集一次整个流出物，持续15分钟。125I-ANP加载后的流出曲线符合双指数衰减模型（Y(to)=Y(t)e-b11t + Y(t)e-b2t）。肺对心钠素的摄取/释放可能参与调节全身浓度，从而影响心钠素的肾脏及其他作用。
