Shared Flashcard Set

Details

Metabolic Homeostasis I & II
glycogen, fuel metabolism, and hormonal regulation
10
Medical
Graduate
09/10/2009

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Cards

Term
Advantages of Glucose storage as Glycogen
Definition

1. Fast mobilization

2. can be metabolized aerobically and anaerobically

3. directly maintain blood glucose levels

Term
disadvantage of Glycogen
Definition

1. hydroscopic, holds alot of water weight

2. only for short term storage

Term

Glycogen mobilization

4 enzymes

Definition

1. glycogen phosphorylase removes 1 gucose from the nonreducing end, adds a P to C1

2. Phosphoglucomutase

moves P to C6

3. Debranching enzyme

moves 3 Glc off side chain

 and removes branching Glc to free Glc, +ΔH, slow

1-4 formation >1-6 break

4. Glc6-phosphatase 

Glc6P-> Glc

only way Glc can eter blood

Term

Glycogen formation

4 enzymes

Definition

1. UDP-Glucosepyrophosphorylase

activates Glc, Glc1P->UDP-1-Glc

2. Glycogen synthase adds UDPGlc to glycogen, give off UDP but requires a primer

3. Glycogenin form enither 8 Glc chain by adding first UDPGlc to tyrosine, makes primer

4. Glycogen branching enzyme moves 8 Glc, forms 1-6 bond, breaks 1-4, -ΔH fast

Term

Regulation of Glycogen Phosporylase

2 enzymes

Definition

1. Phosphorylase kinase

adds P to active GPb-->GPa

2. phosphorylase kinase activated by PKA, Glucagon, AMP Ca

3. Phosphrylase phosphatase removes P from GPa (->GPb) and phosphorylase kinase, activated by insulin

Term

Glycogen Synthase regulation

2 enzymes

Definition

1. GSK3 adds P to GS, Deactivates Insulin blocks its activity

2. Phosphorylase phosphatase removes P, activates it

turned on by insulin, Glc, Glc6P

turned off by Glucagon epineph. 

Term
Hexokinase IV in liver
Definition
Low activity when there is low Glc becasue you want the liver to export Glc to the blood, not to have it go through glycolysis
Term
Insulin effects
Definition

1. glycogen synthesis

2. promote Glc uptake by cells

3. promote uptake of branched amino acids 

4. promote protein synthesis 

Term
Glucagon effects
Definition

1. mostly affects liver

2. stimulate glycogen breakdown

3. inhibits glycogen synthesis

4. inhibits fatty acid synthesis

5. stimulate gluconeogensis

6. activated lipase in fat cells, promotes fatty acid mobilization

Term
epinephrine effects
Definition

1. similar to glucagon but affects muscle cells

2. stimulate glycogen break down and fat breakdown

3. stimulate glucagon secretion

4. inhibits Glc uptake

5. cuase liver to release Glc

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