**Core Concept**
GLUT2 receptors are a type of glucose transporter protein that plays a crucial role in glucose homeostasis by facilitating the uptake of glucose into the liver, kidneys, and pancreas. These receptors are specifically expressed in the basolateral membrane of hepatocytes and pancreatic beta cells, allowing for the uptake of glucose from the bloodstream.

**Why the Correct Answer is Right**
GLUT2 receptors are involved in the sensing of glucose levels in the blood and the subsequent regulation of glucose homeostasis. They facilitate the uptake of glucose into the liver, where it can be stored as glycogen or converted to glucose-6-phosphate, which can be used for energy production or glycogen synthesis. In pancreatic beta cells, GLUT2 facilitates the uptake of glucose, which triggers the closure of ATP-sensitive potassium channels, leading to an increase in intracellular calcium and the subsequent release of insulin.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because GLUT2 receptors are not primarily involved in glucose uptake into muscle and fat cells, which is the function of GLUT4 receptors.
**Option B:** This option is incorrect because GLUT2 receptors are not directly involved in the regulation of blood glucose levels through the release of insulin or glucagon.
**Option C:** This option is incorrect because GLUT2 receptors are not primarily involved in the reabsorption of glucose in the proximal convoluted tubule of the kidneys.

**Clinical Pearl / High-Yield Fact**
GLUT2 receptors are also involved in the regulation of glucose homeostasis during fasting and feeding states, and their dysfunction has been implicated in various metabolic disorders, including diabetes mellitus.

**Correct Answer: D. GLUT2 receptors are involved in glucose homeostasis by facilitating the uptake of glucose into the liver, kidneys, and pancreas.**