PSL201Y1 Lecture Notes - Lecture 31: Renal Glucose Reabsorption, Distal Convoluted Tubule, Proximal Tubule
Document Summary
Most transport in nephron is mediated by membrane proteins which exhibit 3 characteristics of mediated transport including saturation, competition and specificity. Specificity=ability of protein carrier to move only 1 type of molecule or group of related molecules like glucose transporters can move glucose as well as a variety of 6 and 5 carbon sugars but can"t move dissacharides like maltose. Competition glucose transport moves a family of monosaccharides it has a preference for 1-2 molecules. Saturation maximum rate of transport that occurs when all available carriers occupied with substrate (saturated with substrate) Plasma glucose concentration is about 100 mg/dl filtered load of glucose is about 125 mg/min. Transport maximum for glucose reabsorption is 375 mg/min typical renal threshold is 300 mg/dl. Reabsorption in the distal tubule 180l filtered per day is already reabsorbed by time it comes to distal tubule more reabsorption of na+ and water but much of this reabsorption is regulated.
