Goodman B E, Anderson J L, Clemens J W, Kircher K J, Stormo M L, Waltz J S, Waltz W F, White J W
Department of Physiology and Pharmacology, School of Medicine, University of South Dakota, Vermillion 57069.
J Appl Physiol (1985). 1994 Jun;76(6):2578-85. doi: 10.1152/jappl.1994.76.6.2578.
The purpose of this study was to characterize phloridzin- and amiloride-sensitive transport across blood-gas barrier of hamster and rat lungs. Air spaces of isolated perfused lungs were instilled with a solution containing 22Na or L-[3H]glucose, D-[14C]glucose, and fluorescein isothiocyanate-labeled dextran. Apparent permeability-surface area products (PS) were calculated. Phloridzin (Na(+)-dependent D-glucose transport inhibitor) had no effect on D-glucose or sodium transport out of air spaces in hamster lungs. In contrast, in rat lungs, phloridzin decreased PS for D-glucose by 89% and that for Na by 28%. Trapping of 14CO2 in vascular samples was measured to estimate metabolism. Unlabeled air space D-glucose increased appearance of perfused D-[14C]glucose in air spaces of rat lungs. We conclude that Na(+)-dependent D-glucose transport is important for D-glucose uptake in rat lungs but not in hamster lungs. In hamster lungs, amiloride (Na+ transport inhibitor) also decreased PS for sodium, but drugs known to stimulate sodium transport in rat lungs had no effect. Thus, species differences in active transport processes exist in the distal air spaces of mammalian lungs.
本研究的目的是描述根皮苷和氨氯吡咪敏感的转运过程，该转运过程发生在仓鼠和大鼠肺脏的血气屏障上。向离体灌流肺的气腔中注入含有22Na或L-[3H]葡萄糖、D-[14C]葡萄糖以及异硫氰酸荧光素标记的葡聚糖的溶液。计算表观通透率-表面积乘积（PS）。根皮苷（一种Na(+)依赖性D-葡萄糖转运抑制剂）对仓鼠肺脏气腔中D-葡萄糖或钠的转运没有影响。相反，在大鼠肺脏中，根皮苷使D-葡萄糖的PS降低了89%，使钠的PS降低了28%。通过测量血管样本中14CO2的滞留量来估算代谢情况。未标记的气腔D-葡萄糖增加了灌流的D-[14C]葡萄糖在大鼠肺脏气腔中的出现量。我们得出结论，Na(+)依赖性D-葡萄糖转运对大鼠肺脏摄取D-葡萄糖很重要，但对仓鼠肺脏则不然。在仓鼠肺脏中，氨氯吡咪（一种Na+转运抑制剂）也降低了钠的PS，但已知能刺激大鼠肺脏钠转运的药物却没有作用。因此，哺乳动物肺脏远端气腔中主动转运过程存在物种差异。
