Micro-determination of inulin concentration in a solution containing lissamine green.

Micropuncture technique has contributed to our understanding of renal physiology. Particulary the microphotometric determination of the inulin concentration in tubular fluid collected through a micropunc ture technique is a key point for the analysis of the water movement across the tubular cell membrane. Hilger et al. (1). Vurk and Pergam (2) have developed their methods In the experiment to be reported now was attempted to investigate the effect of lissamine green on the determination of inulin concentration, because the tubular fluid contained a dye of lissamine green which was injected into the tubular lumen, in order to identify a tubular segment. A method of microfluorophotometer was applied. In the first experi mental series the test solution were prepared as follows: Four test solution, containing 1, 2, 3, 4 and 5 mg/ml inulin in distilled water were prepared and ilssamine green was added further to each solution (See Fig. 1). Ten nano liter of the test solution was mixed with 2.5 pl of Dimedone solution (5 mg/ml in phosphoric acid) and measured the inulin concentration using AMINCO type fluorophotometer following the Vurk's method. The results were summarized in Fig. 1-a. The values of each series of the test solution showed a lineal correlation with a serial concentration of inulin and the differences of the values between each other were not observed. In the second serius of the experiments, the same test solutions were used, but 25 nl of each test solution was mixed with 2.5 pl Dimedone solution. The results were summarized in Fig. 1-b. As shown in this Fig., the values decreased according to the increasing of the concentration of dye. The high concentration