Glucose transporter in myocyte is:
**Core Concept**
Glucose transporters (GLUTs) are a family of membrane proteins that facilitate the movement of glucose across cell membranes. In cardiac myocytes (heart muscle cells), a specific GLUT is responsible for glucose uptake to meet the high energy demands of these cells.
**Why the Correct Answer is Right**
The correct GLUT in myocytes is GLUT4. This transporter is insulin-responsive and plays a crucial role in glucose homeostasis. When insulin binds to its receptor, it triggers a signaling cascade that ultimately leads to the translocation of GLUT4 to the cell surface, increasing glucose uptake in myocytes. This process is essential for maintaining normal blood sugar levels, especially in response to increased energy demand during exercise or stress.
**Why Each Wrong Option is Incorrect**
* **Option A:** This option is not provided, so we'll skip it.
* **Option B:** This is incorrect because GLUT2 is primarily found in the liver and pancreas, where it plays a role in glucose sensing and regulation of glucose production.
* **Option C:** This is incorrect because GLUT1 is widely distributed in various tissues, including the brain and red blood cells, but it's not the primary glucose transporter in myocytes.
**Clinical Pearl / High-Yield Fact**
In the context of heart disease, impaired glucose uptake in myocytes can contribute to cardiac dysfunction, particularly in diabetic patients. Understanding the role of GLUT4 in glucose homeostasis is essential for managing patients with diabetes and cardiovascular disease.
**Correct Answer: C. GLUT4**