Does adrenaline increase or decrease blood glucose level?

[kevv]

I understand that adrenaline could stimulate breakdown of glycogen in liver and skeletal muscles,
but at the same time it could stimulate glycolysis in skeletal muscles
so will the blood glucose level increase or decrease?

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[curvesetter]

The whole point of sympathetic activation (which increases adrenaline in the bloodstream) is to make energy available for the fight or flight response. Acutely, sympathetic activation leads to an increase in blood glucose levels. Of course, there's no use to having increased blood glucose if it isn't converted into a more readily useable form of energy (ATP!). So basically, glycogen is broken down into glucose which now needs to undergo glycolysis to power the motor proteins in the muscle fibers.

 

[premedkid1994]

increase blood glucose levels.

Adrenaline and glucagon are the two triggers for glycogenolysis. They both stimulate glycogen phosphorylase

 

[kevv]

The whole point of sympathetic activation (which increases adrenaline in the bloodstream) is to make energy available for the fight or flight response. Acutely, sympathetic activation leads to an increase in blood glucose levels. Of course, there's no use to having increased blood glucose if it isn't converted into a more readily useable form of energy (ATP!). So basically, glycogen is broken down into glucose which now needs to undergo glycolysis to power the motor proteins in the muscle fibers.

So on glycogen breakdown, glucagon and epinephrine both phosphorylate glycogen synthetase and glycogen phosphorylase, such that glycogen phosphorylase is active while glycogen synthetase is inactive, leading to the breakdowwn of glycogen into glucose

Then, on glycolysis, insulin and epinephrine both lead to increase of fructose-2,6-bisphosphate, so that phosphofructokinase-1 is stimulated, and hence glycolysis is stimulated.

1) Am I correct?

2) Also, on glyolysis, insulin brings about its effect by activating phosphoprotein phosphatase which then activated PFK-2.
Does epinephrine act in same pathway as well?


Thank you!!

 

[deleted738762]

For the initial question-
I know it's already answered, but you could have derived the answer on your own. If epi stimulates glycolysis, then surely blood glucose will increase so it can travel to cells.

Unless I'm missing something.

 

[kevv]

For the initial question-
I know it's already answered, but you could have derived the answer on your own. If epi stimulates glycolysis, then surely blood glucose will increase so it can travel to cells.

Unless I'm missing something.

I was just not sure which effect is bigger - consumption of blood glucose due to glycolysis in cells, or addition to blood glucose due to glycogenolysis.

 

[pink_pony47]

I was just not sure which effect is bigger - consumption of blood glucose due to glycolysis in cells, or addition to blood glucose due to glycogenolysis.

The body does both glycolysis and glycogenolysis until it has enough glucose for the yield of ATP that it needs. In a post-prandial state, glycolysis would probably be the faster process because hexokinase is inhibited by glucose-6-phosphate and the rate of glucokinase activity is proportional to the concentration of glucose in the blood.

 

[pink_pony47]

For the initial question-
I know it's already answered, but you could have derived the answer on your own. If epi stimulates glycolysis, then surely blood glucose will increase so it can travel to cells.

Unless I'm missing something.

Epi also stimulates glycogenolysis by activating glycogen phosphorylase.