Final answer:
The sodium and glucose cotransporter, also known as the SGLT, is mainly located in the proximal convoluted tubule of the kidney and the small intestine, where it facilitates the reabsorption of glucose alongside sodium through secondary active transport.
Step-by-step explanation:
The sodium and glucose cotransporter is located primarily in the kidneys and the small intestine. Within the kidney, it is found in the proximal convoluted tubule (PCT) where it functions in the reabsorption of glucose from the lumen to the interstitial space. This cotransporter, known as SGLT (Sodium-Glucose Transporter), facilitates the secondary active transport of glucose against its concentration gradient by utilizing the energy derived from the movement of sodium ions down their electrochemical gradient. In the PCT, about 67 percent of water, Na+, and K+ entering the nephron are reabsorbed along with nearly 100 percent of glucose, amino acids, and other vital substances like vitamins.
The symport system works on the apical surface of the renal tubular cells, alongside other substances, where glucose and sodium bind simultaneously to the symport proteins and are transported in the same direction towards the interstitial space. The Na+/K+ ATPase pumps on the basal surface actively pump sodium out of the cell to maintain a low sodium concentration inside the cell, which is essential for the continual functioning of the sodium-glucose symporter.