After overnight fasting, levels of Glucose transporters are reduced in
**Question:** After overnight fasting, levels of Glucose transporters are reduced in
A. Liver
B. Muscles
C. Brain
D. Blood vessels
**Correct Answer:** **C. Brain**
**Core Concept:** Glucose transporters are proteins that facilitate the movement of glucose across biological membranes (e.g., cell membranes). They play a crucial role in maintaining glucose homeostasis in the body. In humans, three main types of glucose transporters exist: SGLT1, GLUT1, and GLUT3.
**Why the Correct Answer is Right:** In the context of overnight fasting, the body's primary goal is to conserve glucose for essential functions, such as maintaining brain function and preventing hypoglycemia. The brain is the primary site where glucose utilization is required for neuronal activity and does not store glucose effectively. Therefore, glucose transporters in the brain are reduced during fasting to conserve glucose for essential functions.
**Why Each Wrong Option is Incorrect:**
A. Liver: While the liver plays a significant role in glucose regulation and storage, it adapts to fasting by increasing gluconeogenesis (glucose production) and glycogen synthesis, which compensates for the reduced glucose uptake in the liver.
B. Muscles: Although muscles require glucose for energy production, they adapt to fasting by breaking down glycogen stored in the muscles into glucose (glycogenolysis) to provide energy.
D. Blood vessels: Reducing glucose transporters in blood vessels is not a relevant response to fasting, as blood vessels primarily maintain blood glucose levels, not directly consume glucose for energy.
**Clinical Pearl:** Understanding glucose transporter adaptations during fasting is crucial for managing patients with diabetes who require careful monitoring of glucose levels and adjusting medications based on blood glucose levels.