Na+ Glucose transporter is-
**Core Concept**
The sodium-glucose cotransporter (SGLT) is a type of transport protein that plays a crucial role in the reabsorption of glucose in the kidneys. It uses the energy from the concentration gradient of sodium ions to facilitate the transport of glucose against its concentration gradient.
**Why the Correct Answer is Right**
SGLT1 (Sodium-glucose cotransporter 1) is a specific type of SGLT found in the small intestine and proximal convoluted tubule of the kidneys. It has a 1:1 stoichiometry, meaning it transports one sodium ion into the cell for every glucose molecule it transports into the cell. This process is essential for glucose reabsorption in the kidneys and for glucose absorption in the small intestine.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is not a sodium-glucose cotransporter. The sodium-potassium pump (Na+/K+-ATPase) is a different type of transport protein that uses ATP to pump sodium out of the cell and potassium into the cell.
**Option B:** This option is not a sodium-glucose cotransporter. The glucose transporter 2 (GLUT2) is a facilitative glucose transporter that does not use the sodium gradient to transport glucose.
**Option C:** This option is not a sodium-glucose cotransporter. The sodium-calcium exchanger (NCX) is a different type of transport protein that exchanges sodium ions for calcium ions.
**Clinical Pearl / High-Yield Fact**
SGLT inhibitors, such as phlorizin, have been used to study the role of SGLT in glucose reabsorption. Understanding the mechanism of SGLT1 is essential for the treatment of diabetes mellitus, where reabsorption of glucose in the kidneys is impaired.
**Correct Answer:** SGLT1