Faubert P F, Chou S Y, Porush J G
Department of Medicine, Brookdale Hospital Medical Center, Brooklyn, New York.
Kidney Int. 1987 Oct;32(4):472-8. doi: 10.1038/ki.1987.234.
We examined in anesthetized dogs the effects of left (L) intrarenal artery infusion of angiotensin II (AII) on renal hemodynamics, urinary concentration and Na excretion, and papillary plasma flow (PPF) (measured by the albumin accumulation technique) in both kidneys. Following AII infusion (0.5 ng/kg/min) into the L renal artery, urinary Na excretion decreased and osmolality increased slightly ipsilaterally, whereas Na excretion did not change significantly and osmolality decreased in the right (R) kidney. PPF was significantly lower in the L compared to the R kidney. When saline loading was superimposed on L intrarenal AII infusion, there was a blunted natriuretic response ipsilaterally with a significantly smaller decrease in urine osmolality compared with the R kidney. PPF increased significantly in the R, but not in the L kidney. Finally, AII blockade with saralasin prior to AII infusion and saline loading prevented the differences between the two kidneys, including PPF. In all groups GFR and renal blood flow did not differ between the two kidneys before or after AII. These data suggest that AII regulates regional blood flow in the medulla, and that the exogenously administered AII induces papillary ischemia, which serves to preserve medullary hypertonicity, preventing an increase in PPF during saline loading, and possibly contributing to the diminished natriuretic response.
我们在麻醉犬身上研究了左肾动脉输注血管紧张素 II（AII）对双侧肾脏的肾血流动力学、尿浓缩及钠排泄以及乳头血浆流量（PPF，通过白蛋白蓄积技术测量）的影响。向左肾动脉输注 AII（0.5 纳克/千克/分钟）后，同侧尿钠排泄减少，尿渗透压略有升高，而右肾钠排泄无显著变化，尿渗透压降低。左肾的 PPF 显著低于右肾。当在左肾内输注 AII 的基础上增加盐水负荷时，同侧利钠反应减弱，与右肾相比，尿渗透压降低幅度明显较小。右肾的 PPF 显著增加，而左肾未增加。最后，在输注 AII 和盐水负荷前用沙拉新阻断 AII 可消除两肾之间的差异，包括 PPF。在所有组中，AII 处理前后两肾的肾小球滤过率和肾血流量均无差异。这些数据表明，AII 调节髓质区域血流，外源性给予的 AII 诱导乳头缺血，这有助于维持髓质高渗状态，在盐水负荷期间防止 PPF 增加，并可能导致利钠反应减弱。
