Fat Metabolism During Exercise W3 Flashcards
Where do fatty acids come from?
Blood stream
Triglycerides stored in muscle
Where are fatty acids in the blood stream derived from?
Adipose Triglyceride stores
What is the conversion of fatty Acyl-CoA?
Beta-oxidation
What happens when there is increased fatty oxidation in the plasma?
Decrease in the breakdown of muscle triglycerides
What happens when a drug is taken which blocks mobilisation of fatty acids from adipose tissue?
Increased reliance on intra-muscular triglyceride stores
What does blocking of fatty acid mobilisation from adipose tissue?
Increase glycogen utilisation due to reduced plasma fatty acid availability
What are enzymes which breakdown triglycerides?
Lipases
What are the 2 key lipases in adipose tissue and skeletal muscle?
ATGL
HSL
What is ATGL?
Found in both skeletal muscle and adipose tissue
Primarily involve in breaking down triglycerides
What is HSL?
Regulated by key hormones
Attacks the diglycerides
How does FFA uptake occur?
Facilitated Diffusion
What are the different protein transporters for FA?
FABP
CD36
FATP
What are the determinants of skeletal muscle fatty acid uptake during exercise?
Fatty acids
Muscle ability to oxidise
FA transporters
Carnitine, CPT activity
Beta-oxidative capacity
What are FABP and CD36?
Fatty acid binding proteins
What is FATP?
Fatty acid transport protein
What are proteins involved in during fatty acid uptake?
Transporting the fatty acids across the sarcolemma, cytosol and mitochondrial membrane
How does CD36 specifically transport fatty acids?
Carnitine
CPT enzyme
What CD36 facilitate?
The mitochondrial entry of fatty acids to be oxidised
What does beta-oxidation involve?
Converting fatty acyl-CoA to acetyl-CoA
What assists beta-oxidation?
HAD
What does the amount of HAD determine?
Amount of fatty acid you can oxidise
Where is HAD found?
Mitochondria
What is the main role of carnitine?
To transport fatty acids into the mitochondria
When is carnitine used?
When there is a large increase in rate of CHO utilisation and acetyl-CoA production
What is the crossroad of CHO and Fat metabolism?
Carnitine
What does carnitine increase when it becomes a buffer?
Acetyl Carnitine
What does Acetyl Carnitine increase?
Acetyl-CoA
What increases HAD?
Mitochondrial number in muscle
What exercise intensity increases fat oxidation?
Moderate
What exercise intensity decreases fat oxidation?
High
What does the lowest exercise intensity heavily rely on?
Plasma FA
Minor contribution from muscle triglyceride
Why does fat oxidation reduce with increased exercise intensity?
Reduced plasma FA availability
Reduced Carnitine availability
Increased rate of glycogen breakdown
Increased adrenaline
Increased sympathetic nerve activation
What does increases in an individual glycolytic flux inhibit?
CPT activity
Mitochondrial uptake
What happens post-exercise involving CHO?
CHO metabolism reduces
Fat metabolism increases
How is a increased in reliance of intramuscular triglycerides shown during exercise?
When the increase in fatty acid uptake is lower than increase in fat oxidation
How does training effect muscle FA uptake during exercise?
Increases transport proteins in muscle
Increases mitochondrial oxidative capacity
Increases HAD
Where does exercise training increase oxidation?
Blood plasma free fatty acids
Intramuscular triglycerides
What does increases in HAD and mitochondrial oxidative capacity drive?
Fatty acid uptake in contracting muscle
What contributes to why regular exercises reduce body mass?
The increased stability of fat to be oxidised
