About $65-80 \%$ of the filtrate is reabsorbed in proximal convoluted tubule. Approximately two-third of filtered water is reabsorbed. Solutes like glucose, amino acids, vitamins, ketobodies, acetoacetic uric acid, chlorides, sodium, potassium, phosphates, etc., of the filtrate are reabsorbed in the body by diffusion and active transport. The filtrate becomes isotonic to blood plasma.