Quizbowl science/Biology/Epinephrine

Epinephrine or adrenaline is an amino acid derivative hormone (polar). It is released from the adrenal medulla.

Functions

• Acts on liver cells to increase blood glucose by:

1. 1. increasing glycogen breakdown and
   2. increasing gluconeogenesis.

• Acts on muscle cells to make ATP by

1. 1. increasing glycogen breakdown
   2. increasing glycolysis
   3. increasing beta-oxidation (breaking down fatty acids to get energy)

Basically, the liver makes glucose, and the muscle breaks down that glucose, so ATP is available for fight-flight.

Mechanism

Epinephrine binds a G-protein coupled receptor, activating adenylate cyclase, which produces cAMP from ATP. This causes protein kinase A to become more active. PKA phosphorylates:

1. 1. makes glycogen synthase less active
   2. activates phosphorylase kinase -- makes glycogen phosphorylase more active (involved in glycogen breakdown -- glycogenolysis)