Question

(A) Describe the hallmarks of the GLUT transporter – a passive glucose transporter, and the basis behind glucose transport in erythrocytes. (4 pts); (B) How does insulin regulate glucose transport and affect GLUT transporter?

Answer 1

There are mainly two type of GLUT transporters

1)Facilitated bidirectional transporters

GLUT 1 - seen in Brain , kidney , colon , placenta , erythrocyte-Uptake of glucose

GLUT2 - liver , pancreas,small intestine -rapid uptake and release of glucose

GLUT 3 -Brain,kidney , placenta - uptake of glucose

GLUT 4 - adipocyte, skeletal muscle , heart - insulin dependant intake of glucose

GLUT 5 - small intestine - -absorption of glucose\

2)sodium dependant unidirectional transporter - small intestine and kidney - uptake of the glucose from the small intestine and reabsorption f the glucose from teh proximal convoluted tubule of the kidney

The main Glucose transporter present over the Erytrocyte is GLUT1.

Erythrocyte requires glucose for the production of the energy , so it need a constant supply of glucose , whenever the glucose concentration of the Erythrocyte decreases , the GLUT1 activated and there will passive transport of the glucose through the GLUT1.

2Q)Insulin is a hormone secreted by the pancreatic Beta cell for converting the excess glucose in the blood stream to Glycogen.

Insulin will increase the uptake of glucose by the Adipocyte, Skeletal muscle and Heart through the GLUT 4 transporter.

if there is a deficiency of insulin , the glucose uptake by the adipocyte , skeletal muscle will be reduced and the blood contain high amount of glucose result in Hyperglycemia.