## **Core Concept**
The question pertains to the regulation of glucose transporter proteins (GLUTs) in response to fasting. GLUTs are crucial for glucose transport across cell membranes, and their expression and activity can be influenced by metabolic states such as fasting.

## **Why the Correct Answer is Right**
During overnight fasting, the body's primary goal is to maintain blood glucose levels within a narrow range. GLUT2, primarily found in hepatocytes and pancreatic beta cells, plays a significant role in glucose sensing and glucose-stimulated insulin secretion. Fasting leads to a decrease in insulin levels and an increase in glucagon levels. This hormonal shift results in reduced glucose uptake in certain tissues and increased glucose production in the liver. GLUT2 expression is indeed influenced by the fasting state, as it is involved in the regulation of glucose metabolism in the liver and pancreas.

## **Why Each Wrong Option is Incorrect**
- **Option A:** This option is incorrect because the specific GLUT subtype affected by fasting is not identified here, making it an unclear choice.
- **Option B:** This option might seem plausible but does not accurately reflect the specific GLUT subtype that is reduced in response to fasting.
- **Option D:** Similarly, this option does not accurately specify the GLUT subtype affected by fasting.

## **Clinical Pearl / High-Yield Fact**
A key point to remember is that GLUT4, primarily found in adipose tissue and skeletal muscle, is significantly affected by insulin levels; its translocation to the cell surface is increased by insulin. However, the question focuses on the effect of fasting on GLUTs, particularly highlighting GLUT2's role in the liver and pancreas.

## **Correct Answer:** .