Question

Using epinephrine as an example, explain how nonsteroid hormones act via second messengers, including the roles of adenylate cyclase, cyclic AMP, G proteins and cAMP dependent protein kinase.

Answer 1

Epinephrine, a nonsteroid hormone, utilizes cAMP as a second messenger to activate cellular responses through the activation of G-proteins, adenylate cyclase, and cAMP-dependent protein kinase.

Step-by-step explanation:

Cyclic adenosine monophosphate (cAMP) is a second messenger used by nonsteroid hormones like epinephrine.

When epinephrine binds to its receptor on the cell membrane, it activates a G-protein, which in turn activates adenylate cyclase (also known as adenylyl cyclase).

Adenylate cyclase converts adenosine triphosphate (ATP) to cAMP. cAMP acts as the second messenger and activates a protein kinase called cAMP-dependent protein kinase (PKA).

This PKA initiates a phosphorylation cascade, where multiple protein kinases phosphorylate various cellular proteins.

This phosphorylation can activate or inhibit certain enzymes and metabolic pathways in the cell, leading to a cell-specific response.

Overall, nonsteroid hormones like epinephrine use second messengers like cAMP and cAMP-dependent protein kinase to transmit signals and regulate cellular processes.