4 Glucose Transporters

Question 1

GLUT1

Answer 1

Location:
Nearly all tissues, especially fetal cells and erythrocytes

Functions:
Baseline Glucose Uptake

Expression increases when glucose is low

Question 2

GLUT2

Answer 2

Location:
Liver cells, pancreatic β cells, kidney cells

Functions:
Bidirectional transport for glycolysis/glycogenolysis and gluconeogenesis

Glucose sensor

Question 3

GLUT3

Answer 3

Location:
Neurons, Placenta

Function:
High glucose affinity
Transports glucose into cell even when extracellular concentrations are low

Question 4

GLUT4

Answer 4

Location:
Skeletal muscle, cardiac muscle, adipose tissue

Function:
Glucose storage as glycogen or triglycerides

Upregulated by increased glucose levels and increased Insulin levels
Primarily expressed shortly after meals when BGL and insulin levels are high
Insulin-Sensitive

In type II diabetes, GLUT4 transporters become insensitive to insulin and stop being expressed during normal insulin levels
This makes it difficult to combat spikes in blood sugar.

Question 5

Type II Diabetes affects which glucose transporter? How?

Answer 5

GLUT4;
GLUT4 transporters become insensitive to insulin and stop being expressed during normal insulin levels
This makes it difficult to combat spikes in blood sugar because GLUT4- which uptakes glucose- is not being expressed.