用微量蒽酮法测定肾小管液中的微量菊糖

A MODIFIED MICROANTHRONE METHOD FOR THE DETERMINATION OF INULIN ON NANOGRAM SCALE

建立微量菊糖测定方法,是应用肾小管微穿刺技术从肾单位水平进行肾脏生理研究的一个技术基础。本实验对Dirks等人采用的微量蒽酮法作了改进。在752-C型分光光度计的光路上安置一个微量比色管,对10μl容积的蒽酮菊糖反应液进行比色。当菊糖含量在2ng至32ng范围内,菊糖含量与吸光度直线性关系(r>0.999)。菊糖平均回收率为101.2±3.5％,表明整个测定系统是准确的。在蒽酮菊糖反应液中加入一定量的肾小管液对菊糖的测定无明显干扰,因此在实际测定时,可将含菊糖的肾小管液直接与蒽酮试剂反应。在21只大鼠的近曲小管末端作微穿刺,用上述微量蒽酮法测得单个肾单位肾小球滤过率为34.9±1.8nl/min,与文献报道的范围符合,说明本方法适用于肾脏生理的研究。

The establishment of a method of determining minute amount of inulin onnanogram scale is essential for applying micropuncture technique to kidney re-search. In this experiment, we modified a classical microanthrone method whichwas used by Dirks et al. to determine inulin contained in tubular fluid. A spec-trophotometer was installed with a special microcuvette to suit the colorimetry of10 μl solution. Linear relation between inulin concentration and absorption wasobserved in the range of inulin concentration from 2 to 32 nl per 10 μl anthronereagent. The accuracy of this microanthrone method was evaluated with inulinrecovery test, the mean recovery rate being 101.2±3.5%. Since tubular fluid didnot interfere with the determination of inulin, the tubular fluid which containedinulin could be added directly to anthrone reagent in actual practice. The meansingle nephron glomerular filtration rate measured with this modified microanth-rone method in 21 rats was 34.9±1.8 nl / min, which coincided well with the valuesreported in literature. The results indicate that the measurement of inulin withthe above-mentioned microanthrone method is reliable and suitable for the micro-puncture study.