Review 3-Glycogen and Glycogen Metabolism

Question 1

Synthesis and Breakdown of hepatic glycogen use what transporter? What are they stimulated by?

Answer 1

GLUT 2 (insulin independent)
Uptake: Insulin
Breakdown: Glucagon

Question 2

Synthesis and Breakdown of muscle glycogen use what transporter? What are they stimulated by?

Answer 2

GLUT 4 (insulin dependent)
Uptake: Insulin 
Breakdown: Epinephrine or Muscle Contraction

Question 3

Glycogen Phosphorylase

Activation & Deactivation

Answer 3

Active: Phosphorylated
CAMP, PI, Ca2+, Glucagon, Epinephrine
*AMP-binds inactive dephosphorylated form and activates it
(Degradation)

Inactive: Dephosphorylated
Insulin
*High ATP and Glucose-bind to phosphorylated form and inactivate

*=allosteric

Question 4

Glycogen Synthase

Activation and Deactivation

Answer 4

Active: Dephosphorylated
Insulin
*High glucose 6-phosphate-bind to phosphorylated form and activate it

Inactive: Phosphorylated
Glucagon, cAMP, Ca, Diacylglycerol

Question 5

1 Von Gierke’s Disease

1. Defective Enzyme
2. Affected Organ
3. Glycogen
4. Clinical Features

Answer 5

1. Glucose 6-phosphatase
2. liver and kidney
3. increased
4. sever hypoglycemia
   enlarged liver, failure to thrive, gouty arthritis, increased lactate, hyperuricemia, hyperlipidemia, mental retardation

Question 6

3 Cori’s Disease

1. Defective Enzyme
2. Affected Organ
3. Glycogen
4. Clinical Features

Answer 6

1. amylo-1,6-debranching
2. liver and muscle
3. increased
4. hypoglycemia
   like 1

Question 7

6 Hers’ Disease

1. Defective Enzyme
2. Affected Organ
3. Glycogen
4. Clinical Features

Answer 7

1. Phosphorylase
2. liver
3. increased
4. hypoglycemia
   like 1

Question 8

8

1. Defective Enzyme
2. Affected Organ
3. Glycogen
4. Clinical Features

Answer 8

1. phosphoylase kinase
2. liver
3. increased
4. mild hypoglycemia
   mild liver enlargement

Question 9

Storage disorders with increase glycogen?

Answer 9

1,3,6,8

Question 10

5 McArdle’s Disease

1. Defective Enzyme
2. Affected Organ
3. Glycogen
4. Clinical Features

Answer 10

1. Phosphorylase
2. muscle
3. moderate amount
4. limited ability to perform strenuous exercise, painful muscle cramps

Question 11

7

1. Defective Enzyme
2. Affected Organ
3. Glycogen
4. Clinical Features

Answer 11

1. PFK-1
2. Muscle
3. Increased
4. Like 5
   limited ability to perform strenuous exercise, painful muscle cramps

Question 12

What storage diseases affect the muscle?

Answer 12

5,7, and 3

Question 13

2 Pompe’s Disease

1. Defective Enzyme
2. Affected Organ
3. Glycogen
4. Clinical Features

Answer 13

1. 1,4 Glucosidase
2. all organs
3. massive increase
4. cardiorespiratory failure, hypotonia cardiomegaly, death before age 2

Question 14

4 Anderson’s Disease

1. Defective Enzyme
2. Affected Organ
3. Glycogen
4. Clinical Features

Answer 14

1. Branching Enzyme
2. liver and spleen
3. Normal amount; long branches
4. progressive cirrhosis of liver, death before age 2

Question 15

What two storage diseases cause death before age 2?

Answer 15

2, 4

Question 16

Where does the pentose phosphate primarily take place? What does it make?

Answer 16

In RBCS

Makes: NADPH, Ribose-5-P(Synthesis of Purines–>DNA, RNA, ATP, CoA), Intermediates of Glycolysis

Question 17

What is the rate limiting enzyme of Pentose phosphate pathway?

Answer 17

Glucose 6-P-Dehydrogenase

Glucose 6 Phosphate–> 6-Phospho-Gluconate

Question 18

Glucose 6-Phosphate Dehydrogenase Deficiency

1. is associated with what
2. inheritance
3. causes what

Answer 18

1. drug induced hemolytic anemia
2. X-linked
3. increased bilirubin, decreased hemoglobin, increased hemolytic anemia, death

Question 19

What does NADPH do in RBCs

Answer 19

Maintains Glutathione in a reduced state–>helps against oxidative damage

-when NADPH low->high levels of reactive oxygen species

Question 20

What induces oxidative stress in RBCs?

Answer 20

1. oxidative drugs (anti-malarial;dapsone)
2. infection-produces free radicals
3. Favism-consumption of fava benas leads to a hemolytic reaction