Natriumglukostransportörer

Natriumglukostransportörer, often abbreviated as SGLTs, are a family of transmembrane proteins found in various tissues of the body, most notably in the kidneys and the small intestine. Their primary function is to facilitate the transport of glucose across cell membranes, a process that is crucial for cellular energy metabolism.

These transporters operate by coupling the movement of glucose with the electrochemical gradient of sodium ions (Na+). This means that as sodium ions move from an area of high concentration to an area of low concentration, they provide the energy to drive the uptake of glucose against its own concentration gradient. This co-transport mechanism is a form of secondary active transport.

There are different types of SGLTs, with SGLT1 and SGLT2 being the most well-studied. SGLT1 is primarily found in the small intestine, where it plays a vital role in absorbing dietary glucose, and also in the proximal tubules of the kidneys. SGLT2 is predominantly located in the S1 segment of the proximal tubules in the kidneys, responsible for reabsorbing the majority of filtered glucose back into the bloodstream.

In the kidneys, the action of SGLTs is essential for preventing glucose loss in the urine. When blood glucose levels are normal, nearly all filtered glucose is reabsorbed. However, when blood glucose levels exceed the reabsorptive capacity of the SGLTs (a condition known as the renal threshold), glucose will appear in the urine, a symptom observed in conditions like diabetes mellitus. Drugs that inhibit SGLTs, known as SGLT inhibitors, have been developed as a therapeutic strategy for type 2 diabetes by promoting the excretion of glucose in the urine, thereby lowering blood glucose levels.