Which structure is involved in transport of glucose in the kidneys?

The transport of glucose in the kidneys primarily involves GLUT transporters, specifically GLUT2 and SGLT (sodium-glucose co-transporter). These transporters play a crucial role in the reabsorption of glucose from the renal tubular fluid back into the bloodstream.

In the renal tubules, glucose is initially reabsorbed through SGLTs, which utilize the sodium gradient established by Na+/K+ ATPases to transport glucose against its concentration gradient. Once glucose is inside the tubular cells, it can move into the interstitial fluid and then into the bloodstream via GLUT2, which facilitates the passive movement of glucose based on its concentration gradient.

This effective mechanism ensures that glucose, an important energy source, is not lost in urine and is retained by the body during the filtering process in the kidneys. In contrast, other structures such as aquaporins are involved in water transport, ion channels generally handle ion movements rather than glucose, and the plasma membrane itself acts as a barrier rather than a transport mechanism.