Lote C J, McVicar A J, Yardley C P
J Physiol. 1985 Jun;363:303-13. doi: 10.1113/jphysiol.1985.sp015711.
The reliability of the use of p-aminohippurate (PAH) as a clearance marker for the determination of renal plasma flow during saline or dextrose infusion was investigated in conscious and anaesthetized rats. In the conscious rat (wt. 350-400 g) infused for 4 h with 0.85% saline followed by 3 h of 2.5% dextrose, PAH clearance averaged 11.50 +/- 1.45 ml/min during saline infusion and 7.83 +/- 0.82 ml/min during dextrose infusion. The difference was significant (P less than 0.02). Inulin clearance, however, was unchanged. With dextrose as the initial infusate, PAH clearance averaged 5.86 +/- 0.65 ml/min and increased (P less than 0.01) to 8.74 +/- 0.71 ml/min following a change of infusate to saline, although inulin clearance was again unchanged. In separate groups of rats anaesthetized with sodium pentobarbitone, a comparison was made between renal blood flow values calculated from PAH clearance and haematocrit, and those determined simultaneously using an electromagnetic flow probe placed on the left renal artery. During 0.85% saline infusion, the calculated value was 88.1 +/- 8.4% of that measured using the flow probe. During 2.5% dextrose infusion the value determined from PAH clearance was only 47.3 +/- 4.2% of that obtained using the flow probe, and this is significantly (P less than 0.01) lower than the ratio found during saline infusion. In another study, renal venous blood samples were obtained from sodium-pentobarbitone-anaesthetized rats during 0.85% saline or 2.5% dextrose infusions, for calculation of the renal PAH extraction ratio. During saline infusion, PAH extraction averaged 68.3 +/- 2.5%, whereas during dextrose infusion PAH extraction was lower (P less than 0.001) and averaged only 48.8 +/- 3.2%. It is concluded that PAH clearance grossly underestimates renal plasma flow during 2.5% dextrose infusion in the rat.
在清醒和麻醉大鼠中，研究了对氨基马尿酸（PAH）作为清除标记物用于测定生理盐水或葡萄糖输注期间肾血浆流量的可靠性。在体重350 - 400克的清醒大鼠中，先输注4小时0.85%生理盐水，接着输注3小时2.5%葡萄糖，生理盐水输注期间PAH清除率平均为11.50±1.45毫升/分钟，葡萄糖输注期间为7.83±0.82毫升/分钟。差异具有统计学意义（P＜0.02）。然而，菊粉清除率未改变。以葡萄糖作为初始输注液时，PAH清除率平均为5.86±0.65毫升/分钟，在输注液换为生理盐水后升高（P＜0.01）至8.74±0.71毫升/分钟，尽管菊粉清除率再次未改变。在另一组用戊巴比妥钠麻醉的大鼠中，对根据PAH清除率和血细胞比容计算的肾血流量值与使用置于左肾动脉的电磁流量探头同时测定的值进行了比较。在输注0.85%生理盐水期间，计算值为使用流量探头测量值的88.1±8.4%。在输注2.5%葡萄糖期间，由PAH清除率确定的值仅为使用流量探头获得值的47.3±4.2%，且显著低于（P＜0.01）生理盐水输注期间发现的比值。在另一项研究中，在0.85%生理盐水或2.5%葡萄糖输注期间从戊巴比妥钠麻醉的大鼠获取肾静脉血样，用于计算肾PAH提取率。生理盐水输注期间，PAH提取率平均为68.3±2.5%，而葡萄糖输注期间PAH提取率较低（P＜0.001），平均仅为48.8±3.2%。结论是，在大鼠2.5%葡萄糖输注期间，PAH清除率严重低估了肾血浆流量。
