Pancreas is known as a mixed gland. Endocrine functions include production of insulin by beta cells. This hormone affects the metabolism of carbohydrates. What is its effect upon the activity of glycogen phosphorylase (GP) and glycogen synthase (GS)?

Answer options

1. It inhibits both GP and GS
2. It does not affect the activity of GP and GS
3. It inhibits GP and activates GS
4. It activates both GP and GS
5. It activates GP and inhibits GS

Explanation

Glycogen phosphorylase breaks up glycogen into glucose subunits AND glycogen synthase (GS) takes glucose and converts them into long polymers of glycogen. Insulin has a negative effect on GP and a positive effect on GS.