Renal tubular glucose maximum reabsorption test

After the glucose in normal human blood is completely filtered from the glomerulus, all the proximal tubules are actively reabsorbed, and the urine is excreted without sugar. This reabsorption is performed in reverse concentration. The reabsorption mechanism is that the carrier protein (transporter) on the proximal tubule epithelial cell membrane combines with Na + and glucose to form a complex, which can be reabsorbed through the renal tubule cell membrane. blood. Because there is a certain amount of carrier protein on the cell membrane, there is a certain limit on the transport of glucose. When the blood glucose concentration rises to a certain level, the reabsorption capacity of the renal tubules is saturated, and too much sugar cannot be reabsorbed, and urine sugar appears. Even if the blood glucose concentration is higher, the reabsorption value does not increase any more, which is TmG. The TmG value can be obtained by subtracting the amount of glucose appearing in urine in the same unit time from the amount of glucose filtered from the glomerulus per unit time. The value of this value can reflect the number and function of effective nephrons. One of the indicators of end-tubular reabsorption function.