Intro To Metabolism

Question 1

What are the three ways our body regulates metabolic homeostasis

Answer 1

AMPK pathway
MTOR pathway
Insulin pathway

Question 2

Ow will the body respond to low glucose levels?

Answer 2

• By activating the alpha cells of the pancreas to release glucagon
• hypothalamus will send out a signal to release epi, norepi, and cortisol

Question 3

How will your body respond to high glucose?

Answer 3

• -hypothalamus will causes activity of the beta cells of the pancreas to release insulin.
• • the insulin will act on the adipose tissue to release Leptin to decrease appetite and bring glucose levels down.

Question 4

How does insulin get altered?

Answer 4

• -> It goes from the ER and on the way there are disulfide bridges between to parts of the protein
• -> it reaches the Golgi and the parts that were connected by disulfide bonds is chopped off and is called insulin. The remaining part is called the C-peptide.

Question 5

How is the C-peptide used as an indicator of endogenous production vs insulin injection?

Answer 5

Injected insulin does not have the C-peptide on it. So,you can measure the C-peptide if you want to know the amount of indigenous insulin production.

Question 6

IRS-1

Answer 6

Insulin receptor substrate - insulin binds to this.

- from there it can activate either GRB-2 or PI 3-kinase

Question 7

GRB-2

Answer 7

GRB-2 activates RAS, which phosphorylates a target protein and alters gene transcription.
- Glucokinase transcription is increased.

Question 8

PI 3- Kinase

Answer 8

IRS-1 can activate this. It will activate PKB, which will phosphorylate a target protein and cause alterations in protein and enzyme activity such as GLUT4 movement into the plasma as well as dephosphorylation of downstream enzyme such that glycogen synthase will be activated.

Question 9

What is the common thread between GRB-2 and PI 3-Kinase?

Answer 9

Both will induce insulin to be up taken and glycogen synthesis.

Question 10

How do glucagon and epinephrine exert their affects?

Answer 10

Both will bind to G protein receptors. The G protein receptor glucagon will be on The liver. The epinephrine receptor will be on muscle or the liver.

• after that there is a typical G protein response involving adenylyl cyclase, cAMP, PKA etc.
• it gets turned off by a phosphodiesterase

Question 11

Why do coffee and tea increase blood glucose levels?

Answer 11

It inhibits the phosphodiesterase, so glucagon and epinephrine will be able to exert their affects for longer.

Question 12

AMPK

Answer 12

If a cellular stress causes the rate of catabolism to fail to keep pace with the rate of ATP consumption.

• -> we will see increased levels of ADP and AMP.
• -> This causes the activation of AMPK.
• -> AMPK promotes restoration of energy balance by stimulating catabolism and inhibiting ATP-consuming processes.

Question 13

What pathway will be activate in the fed state??

Answer 13

MTOR