fuel mobilisation with glucagon

Question 1

what is the role of adrenline and glucagon in fuel mobilisation

Answer 1

Glucagon - made from cleavage by convertase enzyme in pancreatic beta cells from proglucagon
stimulated: low blood glucose, fasting, stess, excersis
effects: down regulates lipogenesis, upregulates glycogenolysis in liver, upregulates transcription genes for beta oxidation (carnitine acyltransferase)

Adrenline - synthesised from tyrosine in medulla of adrenal gland
- simulated by SNS in stress, also high excersis + low blood glucose

Question 2

What is the process of glycogenolysis in the liver and the muscle

Answer 2

Glycogen phosphorylase releases glucose-1-phosphate -> mutase convertes to glucose -6-p
in mucles: Glucose-6-P used in glycolysis for energy
in liver: glucose-6-phosphotase convertes to glucose -> released to bloodd stream
- Muscle does not have glucose-6phosphotase and cannot regulate

Question 3

How is the pathway for glycogenolysis reset

Answer 3

1. liggand (glucagon) dissociates from GPCR + GTP-> GDP (inactivates g protein)
2. phosphotases dephosphorylate proteins which had been phosphorylated
3. phosphodiester enzyme metabolises cAMP

Question 4

What is the pathway for glycogenolysis

Answer 4

occurs in liver or muscles

Glucagon/adrenline binds to GPCR -> GDP phosphrylated on g-protein -> GTP -> adenylase cyclase releases cAMP -> activates PKA
PKA activates catabolism (glycogen phosphorylase), PKA inhibits anabolism(glycogen synthase)

Question 5

What is the pathway for lipolysis

Answer 5

Occurs in adipocytes

glucagon/adreline binds to GCPR->cAMP->PKA->hormone sensitive lipase -> hydrolysis TAGs
3 FFA released bound to albiunim and 1 glycerol released to liver for lipogenesis

Question 6

What is the role of protein as a fuel

Answer 6

No designated protein fuel stores but 10-15Kg protein in the body
- energy source during starvation
- releases amino acids -> used ketoacids
- eventually leads to tisue damage and or loss of function

Question 7

Contrast between anaerobic and arobic excersis

Answer 7

aerobic: long + low intensity
glucose + FFA used in oxidative metaboliusm for energy

anaerobic: short + high intesnisty
- uses glycolysis + lactate
- no ETC as no O2
- lactate buildup leads to increase H+ ions in cell -> lowes pH

Question 8

What is an aditional short acting energy store

Answer 8

Phosphocreatine - synthesised from Met, Arg, Gly
Stores around 10s of energy in muscles through phosphate bonds
reversable with creatine kinase - resets during rest, used during work