Regulation of Blood Glucose Levels - Glucagon

Question 1

Describe how glucagon increases the blood glucose level back to normal level.

Answer 1

1. Alpha cells in the pancreas detect the low blood glucose level and release the hormone glucagon
2. Glucagon binds to specific protein receptors in the liver cell membrane
3. This activates an enzyme called adenylate cyclase which converts ATP into cAMP
4. • cAMP activates protein kinase A which hydrolyses glycogen to release glucose
   • glucose leaves the liver via glucose channel proteins and enters the blood
   • enzymes form new glucose from amino acids and glycerol
   • respiration rate is reduced to prevent glucose being used up
5. This increases blood glucose level back to normal

Question 2

How is adrenaline similar to glucagon?

Answer 2

When produced by the adrenal glands, adrenaline binds to specific protein receptors in liver and muscle cell membranes and also activates cAMP