Which tissue is NOT a location of the glucose transporter described as regulating insulin release and glucose homeostasis?

• A. Brain
• B. Liver
• C. Kidney
• D. Pancreatic beta cells

Answer: (A)

GLUT2 is a glucose transporter that acts as a glucose sensor and helps regulate insulin release and whole-body glucose balance. It is found in the liver, kidney, and pancreatic beta cells. In beta cells, GLUT2 lets the cell sense rising glucose to trigger insulin release; in the liver and kidney, it supports glucose handling and reabsorption to maintain blood glucose levels. The brain uses different transporters, mainly GLUT1 and GLUT3, to take up glucose for neural function, and these are not the ones involved in insulin signaling or glucose sensing for hormone release. So the brain is not a location where this glucose transporter operates to regulate insulin release and glucose homeostasis.