Question

Glycogen is an important and quickly mobilized source of stored glucose. Glucose is mobilized for ATP generation in muscle in response to epinephrine, which activates Gs. How would inhibitors of cAMP phosphodiesterase affect glucose mobilization in muscle

Answer 1

Glucose mobilization would continue

Step-by-step explanation:

The GTP-bound alpha subunit (Gαs) is a subunit of the heterotrimeric G protein which is required for stimulating the cAMP-dependent pathway through the activation of the membrane-associated enzyme adenylyl cyclase, which in turn catalyzes the synthesis of the second messenger cyclic-3′,5′-adenosine monophosphate (cAMP) from ATP. Moreover, cAMP phosphodiesterase is an enzyme that hydrolyzes cAMP, thereby negatively regulating the levels of this second messenger, which is fundamental for the termination of the signal. In this case, the epinephrine signal initiates glycogen breakdown (glucose mobilization) in muscle cells. In consequence, if the cAMP phosphodiesterase enzyme is inhibited, the concentration of cAMP will persist high even beyond the termination of the signal, thereby glucose mobilization would continue.