The proximal tubules make up a significant portion of the kidneys and they are also the site of<em> active solute secretion, hormone production, and many of the metabolic functions of the kidney</em>. This segment of the nephron in kidney has two main functions: absortion and secretion. <em>A hundread percent of organic solutes, such as glucose and amino acids are reabsorbed</em><em>, that's why they should not be present in his urine.</em>