Question

What is the link between adrenaline and glycogen?

A)	Adrenaline can be converted to glycogen to act as a secondary messenger.

B)	When glycogen bind in excess to liver cells it causes a corresponding release of adrenaline from the adrenal glands.

C)	Binding of adrenaline to receptors results in the eventual hydrolysis of glycogen in muscle cells.

D)	The binding of adrenaline to cells causes a rapid uptake of glycogen and release of glucose in all cells.

E)	None of the above

Answer 1

Correct answer is: (C) Binding of adrenaline to receptors results in the eventual hydrolysis of glycogen in muscle cells.

Explanation: -

Adrenaline, is a hormone and neurotransmitter and binding of adrenaline to a receptor initiates a cascade of cellular reactions. Signal Transduction starts when Adenylyl Cyclase (AC), a membrane bound enzyme, is activated by G-Protein Coupled receptor (GPCR). Adenylyl Cyclase in turn produces Cyclic adenosine monophosphate (cAMP) molecules. The elevated level of cAMP activates Protein kinase A (PKA), through the binding of cAMP to the regulatory subunits. Protein Kinase A phosphorylates the ? subunit of Phosphoryl kinase, which in turn activates glycogen phosphorylase, that leads to the hydrolysis of glycogen in the muscle cells.