Inhibition of Glycolysis by Glucagon

[SuperSaiyan3]

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what up dawgs.

so i was just thuggin around in Kap Test numero dos while i came across dis punk question about the effect of glucagon.

the answer was that glucagon inhibits glycolysis.

Does this make any sense? I thought glucagon was supposed to INCREASE the blood glucose level! Why would it inhibit glycolysis? And where would it get its sugar?

I guess for that part, it would get its sugar by glycogenolysis in the liver.. but still. why?

punkass... SS3

 

[capn jazz]

First of all, the diagram in the question shows that low blood glucose (which would coincide with glucagon release) results in PFK2 being phosphorylated which is its inactive form, thus changing fructose-2,6-bisphosphate back to fructose-6-phosphate.

From there, it will revert back to glucose to be released into the blood stream as free glucose because the purpose of glucagon is to release glucose into the blood stream.

edit: remember, glycolysis does NOT produce glucose, it uses up glucose. so you want to inhibit it if you want to increase circulating glucose for body tissues.

 

[G1SG2]

what up dawgs.

so i was just thuggin around in Kap Test numero dos while i came across dis punk question about the effect of glucagon.

the answer was that glucagon inhibits glycolysis.

Does this make any sense? I thought glucagon was supposed to INCREASE the blood glucose level! Why would it inhibit glycolysis? And where would it get its sugar?

I guess for that part, it would get its sugar by glycogenolysis in the liver.. but still. why?

punkass... SS3

It makes perfect sense. How can glucagon increase blood glucose levels when bad boy glycolysis keeps using up all that glucose and breaking it down?

Glucagon: We need energy (glucose)!
Glycolysis: hehe, I'm using it all up.
Insulin: good job, glycolysis! Keep it up!

Glucagon: screw you glycolysis-I'm inhibiting you!

And that's how the blood glucose level increased. The end.

 

[matth87]

It makes perfect sense. How can glucagon increase blood glucose levels when bad boy glycolysis keeps using up all that glucose and breaking it down?

Glucagon: We need energy (glucose)!
Glycolysis: hehe, I'm using it all up.
Insulin: good job, glycolysis! Keep it up!

Glucagon: screw you glycolysis-I'm inhibiting you!

And that's how the blood glucose level increased. The end.

Wow! thanks for giving me a nice little laugh at 2:33am, yes ive been studying for like 12 hours today lol.

 

[Spiker]

are you working on the old long tests? with like 77 questions on each section?

 

[Dr Gerrard]

Yeah, but whats the point of increasing blood glucose if you cannot use it???

 

[capn jazz]

The process described was in the liver cells, which would be releasing glucose to the blood stream for other tissues/cells to use. Glucagon ONLY acts on liver cells so only liver cells will be giving up their glucose/glycolysis abilities.

 

[Charles_Carmichael]

Yeah, but whats the point of increasing blood glucose if you cannot use it???

The point of raising the blood glucose is mainly to keep the blood glucose levels somewhat constant for the brain to use. Remember that the brain almost exclusively uses glucose as its energy source; it starts using ketone bodies only in extreme situations. So, there needs to be a somewhat constant level of glucose in the blood.

 

[Hemichordate]

So let me see if I have this right:

Glucagon: Inhibit glycolysis, increases gluconeogenesis
Insulin: Increase glycolysis, inhibit gluconeogenesis

Right?

 

[G1SG2]

So let me see if I have this right:

Glucagon: Inhibit glycolysis, increases gluconeogenesis
Insulin: Increase glycolysis, inhibit gluconeogenesis

Right?

👍

 

[0Complications]

The process described was in the liver cells, which would be releasing glucose to the blood stream for other tissues/cells to use. Glucagon ONLY acts on liver cells so only liver cells will be giving up their glucose/glycolysis abilities.

This is a nice little nugget to add to the memory banks. 😉 👍

 

[Charles_Carmichael]

The process described was in the liver cells, which would be releasing glucose to the blood stream for other tissues/cells to use. Glucagon ONLY acts on liver cells so only liver cells will be giving up their glucose/glycolysis abilities.

This is not completely true. While the major actions of glucagon are on the liver, it also acts on adipose tissue to increase lipolysis and decrease fatty acid synthesis. This also shunts substrates towards gluconeogenesis. Glucagon acts on both the liver and adipose tissue. Insulin acts on the liver, adipose tissue, and muscle.

 

[0Complications]

This is not completely true. While the major actions of glucagon are on the liver, it also acts on adipose tissue to increase lipolysis and decrease fatty acid synthesis. This also shunts substrates towards gluconeogenesis. Glucagon acts on both the liver and adipose tissue. Insulin acts on the liver, adipose tissue, and muscle.

When I read that my mind played the voice of Jordon from Audio Osmosis.

But nice follow-up.

 

[JiniInBottle]

In the same kap 2 test, question 142 is still confusing...it's mind boggling😕
If it decreases F-2,6 BP degradation, thus glycolysis...then how can there be an increase in ATP/AMP ratio.
If ATP is high then phosphofructokinase should be inhibited not stimulated.
I think this question is just incorrect....b/c there should be a clear cut answer, right? I hope real AAMC tests are not like this.