Question

Compare and contrast the action of epinephrine vs glucagon binding and signaling from its target GPCR in order to regulate glucose metabolism under stress vs rest conditions.

Answer 1

ANSWER -

The glucagon and epinepherine both follow the same G protein based signalling. although these two molecule have same aim but these two molecules based signalling still have differences .

glucagon based signalling	epinepherine based signalling
1. it mostly occur in the liver 2 this molecule bind on the glucagon receptor	1. it occur in the muscle 2. this molecule binds to the β-adrenergic receptor

both signalling occur as follow -

1. The molecules epinephrine and glucagon bind their specific receptors in the plasma membranes of muscle and liver cells respectively.when these molecule bind to their respective receptor it  activate the α subunit of the heteromeric Gs protein. this activation include the exchange of the GDP by the GTP.

2. This GTP-bound form of the α subunit of Gs activates adenylate cyclase, a transmembrane protein further this enzyme catalyzes the formation of the secondary messenger cyclic AMP from ATP.

3. The increased cytosolic level of cyclic AMP activates protein kinase A by the binding of cyclic AMP to the regulatory subunits, which then dissociate from the catalytic subunits.

4. This activated protein kinase A phosphorylates the β subunit of phosphorylase kinase, which subsequently activates glycogen phosphorylase.

these phosphorylase lead to the break down of the glycogen .

DURING THE RESTING COONDITION -

means where there is no starvation and body dnt require too much energy in (one go example during exercise). In these condition the level of both the glucagon and the epinepherine will remain normal and they dnt show their action .

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