GLUT1

All mammalian tissues

1 mM

Basal glucose uptake

GLUT2

Liver and pancreatic β cells

15−20 mM

In the pancreas, plays a role in the regulation of insulin

In the liver, removes excess glucose from the blood

GLUT3

All mammalian tissues

1 mM

Basal glucose uptake

GLUT4

Muscle and fat cells

5 mM

Amount in muscle plasma membrane increases with endurance training

GLUT5

Small intestine

—

Primarily a fructose transporter