The transpo maximum of glucose in renal tubules during reabsorption?
High-Yield Explanation
The amount reabsorbed is propoional to the amount filtered and hence to the plasma glucose level (PG) times the GFR up to the transpo maximum (TmG). When the TmG is exceeded, the amount of glucose in the urine rises. The TmG is about 375 mg/min in men and 300 mg/min in women. Also know: Glucose, amino acids, and bicarbonate are reabsorbed along with Na+ in the early poion of the proximal tubule. Glucose is typical of substances removed from the urine by secondary active transpo. It is filtered at a rate of approximately 100 mg/min (80 mg/dL of plasma x 125 mL/min). Essentially all of the glucose is reabsorbed, and no more than a few milligrams appear in the urine per 24 h. Ref: Barrett K.E., Barman S.M., Boitano S., Brooks H.L. (2012). Chapter 37. Renal Function & Micturition. In K.E. Barrett, S.M. Barman, S. Boitano, H.L. Brooks (Eds), Ganong's Review of Medical Physiology, 24e.