Glycogen: Metabolism and Disorders Flashcards
What is Glycogen
A polymer made from glucose which serves as a form of Energy Store.
The 2 pathways to mantain blood glucose levels during fasting
Glycogenolysis and Gluconeogenesis
Which human cell can use only glucose as source of energy
Erythrocyte
Where do Glycogenolysis and Gluconeogenesis happen
Liver and muscle cells
What is Glycogenesis
Conversion of glucose molecules into Glycogen
Regulation of Glycogenesis
Allosteric via Glycogen Synthase.
Activated = insulin and cortisol
Inhibited = glucagon and epinephrine.
What is Glycogenolysis
Conversion of Glycogen into glucose molecules
Regulation of Glycogenolysis
Allosteric via Glycogen Phosphorylase.
Activated = glucagon, epinephrine or AMP
Inhibited = insulin, ATP, glucose-6-phosphate
Insulin is implicated in _________ reactions
Anabolic
Glucagon is implicated in ___________ reactions
Catabolic
Fed state increases ________ concentration
Insulin
Fasting state increases ____________ concentration
Glucagon
Insulin promotes which metabolic reactions
Glycolysis
Glycogenesis
Fatty acid synthesis
Protein synthesis
Glucagon promotes which metabolic reactions
Glycogenolysis
Gluconeogenesis
Glucagon type of signal pathway
G-Protein coupled Receptor
First step after Activation of Protein Kinase by glucagon
Activation of Glycogen Phosphorylase
Insulin type of signal pathway
Tyrosine-Kinase receptor
Activation of Protein Phospathase-1 by insulin leads to
Activation of Glycogen synthase
What does the tyrosine-kinase receptor do when stimulated by Insulin
Activation of Protein Phosphatase = Activation of Glycogen Synthase
Von Gierke disease is cause by deficiency of
Glucose-6-phosphatase (LAST STEP in Glycogenolysis)
Which molecule is accumulated in Von Gierke Disease
Glucose-6-phosphate
Von Gierke disease features
Clinic: Severe fasting hypoglycemia + Doll-like faces + Hepatomegaly
Lab: Elevated lactate and uric acid
Pompe disease is cause by deficiency of
Lysosomal alpha 1,4 glucosidase
Pompe disease features
Cardiomegaly + Exercise intolerance + Weakness
Cori disease is caused by deficiency of
Debranching enzyme
Cori disease special feature
Fasitng Hypoglycemia with NORMAL LACTATE levels
McArdle disease is caused by deficiency of
MUSCLE Glycogen Phosphorylase
McArdle disease features
Muscle pain w/ exercise + Myoglobinuria + 2ND WIND EFFECT
What is the final product of HMP Shunt
1 RIBOSE
1 CO2
2 NADPH
What reactant does HMP Shunt use
Glucose-6phospate
Where does HMP Shunt occur
Cytosole
Regulation of HMP Shunt
Allosteric via G-6PD
What is G-6PD Deficiency’s inheritance pattern
X-Linked Recessive
What is G-6PD pathophysiology
Deficiency of G-6PD produces a decreases in Reduced Glutathione leading to Oxidative damage
G-6PD clinical features
Hemolytic anemia in crisis triggered by stressors like Fava Beans, Sulfonamides and infections
