T2 L9: Fed and starved states Flashcards
What is the main source of energy in cells during the absorptive and post absorptive phases of digestion?
In absorptive it’s glucose but after that it’s fatty acids
What happens to excess amino acids entering from the gut?
They are converted to pyruvate and metabolised via the TCA cycle
What is Glycerol from peripheral tissues converted into?
Triacylglycerides
Which protein carries fatty acids from the diet to muscles?
Chylomicrons
Which protein carries fatty acids from the liver to muscles?
VLDL
Which process oxidises fatty acids into acetyl CoA in muscles?
Beta-oxidation
What is the function of lipoprotein lipase (LPL)?
It allows the release of lipids from chylomicrons and VLDL so the lipid material can enter peripheral tissues
What is the function of hormone sensitive lipase (HSL)?
It catalyses the breakdown of triacylglycerides into fatty acids
What effect does insulin have on hormone sensitive lipase (HSL)?
Inhibition
What effect does insulin have on Lipoprotein lipase (LPL)?
Increased activity
How does the brain metabolise glucose in the fed state?
Oxidatively by glycolysis and the TCA cycle to produce ATP
Why cant the brain use fatty acids as a source of energy?
Because fatty acids can’t cross the blood brain barrier
What happens to thyroid hormones in the starved state?
They decrease to slow down the metabolic rate
Why do fatty acids become the main source of energy in the starved state?
To spare the glucose for the brain or other tissues that depend on it
Why is urea synthesis stimulated during the starved state?
To cope with the increased amounts of amino acids entering the liver for breakdown
