Question: what is absorbed in the proximal convoluted tubule?
Answer: The reabsorption in the proximal tubule is isosmotic. In the PCT 65% of water, 100% of glucose, 100% amino acids, 65% of potassium, 65% chloride and 67% of sodium is reabsorbed. This reabsorption occurs due to the presence of channels on the basolateral (facing the interstitium) and apical (facing the lumen).