Insulin dependent entry of glucose is seen in ?
**Core Concept**
Insulin-dependent glucose entry into cells is a key mechanism by which the hormone insulin regulates blood glucose levels. Insulin stimulates the translocation of glucose transporter type 4 (GLUT4) to the cell surface in muscle and adipose tissue, allowing glucose to enter the cell. This process is essential for maintaining normal blood glucose levels, particularly after a meal.
**Why the Correct Answer is Right**
The correct answer involves the action of insulin on glucose transporter type 4 (GLUT4). Insulin binds to its receptor on the surface of muscle and adipose cells, activating a signaling cascade that ultimately leads to the translocation of GLUT4 to the cell surface. Once at the cell surface, GLUT4 facilitates the entry of glucose into the cell through a process known as facilitated diffusion. This process is essential for glucose uptake in the postprandial state and is impaired in insulin resistance and type 2 diabetes.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is likely referring to sodium-glucose cotransporter 1 (SGLT1), which is involved in the uptake of glucose in the small intestine. While SGLT1 is an important glucose transporter, it is not insulin-dependent and is primarily involved in glucose absorption in the gut.
**Option B:** This option is likely referring to glucose transporter type 1 (GLUT1), which is a constitutively expressed glucose transporter found in many tissues, including the brain and red blood cells. GLUT1 is not insulin-dependent and is responsible for basal glucose uptake in these tissues.
**Option C:** This option is likely referring to glucose transporter type 3 (GLUT3), which is a high-affinity glucose transporter found in the brain and placenta. GLUT3 is not insulin-dependent and is responsible for glucose uptake in these tissues.
**Clinical Pearl / High-Yield Fact**
It's essential to remember that insulin resistance and impaired glucose uptake are key features of type 2 diabetes. Understanding the role of insulin-dependent glucose entry into cells is crucial for managing this condition and developing effective treatment strategies.
**Correct Answer: C. Insulin stimulates the translocation of glucose transporter type 4 (GLUT4) to the cell surface in muscle and adipose tissue, allowing glucose to enter the cell.**