Williams W M, Frölich J C, Nies A S, Oates J A
Kidney Int. 1977 Apr;11(4). doi: 10.1038/ki.1977.38.
The stop-flow technique was used in dogs to determine the site of entry of urinary prostaglandins (PG) into tubular fluid. The proximal tubule was localized by the peak (U/PPAH)/(U/PIn) and the distal tubule and collecting duct by the peak U/PIn and the minimum (U/PNa)/(U/PIn). The peak of prostaglandin E (PGE) concentration was located 4.8+/-0.8 (SEM) ml distal to the proximal tubule and 4.6+/-0.8 (SEM) ml proximal to the distal nephron. At its peak, PGE was concentrated 6.3-fold over baseline, whereas inulin was concentrated 1.4-fold at its peak. The height of the PGE peak but not its location was increased by an i.v. infusion of angiotensin II at 20 ng/kg of body wt per min. Indomethacin abolished the PG peak. In a single experiment, prostaglandin F2alpha (PGF2alpha) exhibited an excretion pattern similar to PGE. These data indicate that the site of entry of PG into tubular fluid is most likely in the loop of Henle. This is consistent with the hypothesis that PG synthesized in the medulla can be transported to the cortex via tubular fluid. Whether PG in the tubular fluid can influence renal function remains to be determined.
采用停流技术在犬身上确定尿中前列腺素（PG）进入肾小管液的部位。通过（尿/血浆对氨基马尿酸）/（尿/血浆菊粉）峰值定位近端小管，通过尿/血浆菊粉峰值以及（尿/血浆钠）/（尿/血浆菊粉）最小值定位远端小管和集合管。前列腺素E（PGE）浓度峰值位于近端小管远端4.8±0.8（标准误）毫升处以及远端肾单位近端4.6±0.8（标准误）毫升处。在峰值时，PGE浓度比基线升高了6.3倍，而菊粉在峰值时浓度升高了1.4倍。静脉注射每分钟20纳克/千克体重的血管紧张素II可使PGE峰值的高度增加，但不改变其位置。吲哚美辛消除了PG峰值。在一次实验中，前列腺素F2α（PGF2α）呈现出与PGE相似的排泄模式。这些数据表明，PG进入肾小管液的部位很可能在亨氏袢。这与髓质中合成的PG可通过肾小管液转运至皮质的假说相符。肾小管液中的PG是否能影响肾功能仍有待确定。
