## Core Concept
GLUT (Glucose Transporter) is a family of proteins that facilitate the transport of glucose across cell membranes. These transporters play a crucial role in glucose metabolism and are widely distributed in various tissues. The primary function of GLUT proteins is to facilitate diffusion of glucose down its concentration gradient.

## Why the Correct Answer is Right
The correct answer is related to the characteristics and functions of specific GLUT transporters. For instance, GLUT1 is widely expressed and responsible for basal glucose uptake, GLUT2 is primarily found in the liver and pancreas and has a high Km for glucose, GLUT3 has a high affinity for glucose and is often associated with neurons, and GLUT4 is insulin-responsive and mainly found in adipose tissue and skeletal muscle.

## Why Each Wrong Option is Incorrect
- **Option A:** This option might state a true characteristic of a specific GLUT transporter, such as GLUT1 being expressed in many tissues.
- **Option B:** This could be incorrect based on the specificity of GLUT transporters to certain tissues or their response to insulin.
- **Option C:** This might describe a feature of another GLUT transporter accurately, such as GLUT4's role in insulin-stimulated glucose uptake.
- **Option D:** This option is labeled as the correct answer but without specific details provided in the question, we infer it presents an inaccurate statement about GLUT transporters.

## Clinical Pearl / High-Yield Fact
A key point to remember is that GLUT4 is an insulin-responsive glucose transporter, primarily found in adipocytes and striated muscle (skeletal and cardiac), and plays a critical role in glucose metabolism postprandially.

## Correct Answer: D.