Metabolism 3 – Lipid and liver metabolism & pathologies Flashcards
What are the 3 sources of lipids in the body
- Ingested via diet
- Liberated from adipose tissues (via lipolysis)
- Synthsised in the liver (via de novo lipogenesis)
What occurs to glycerol under fasted conditions
Under fasted conditions, glycerol can be metabolised to generate ATP (in fat, liver, muscle)
How are fatty acids metabolised
Fatty acids are metabolised to ketone bodies via beta oxidation (in the liver)
What occurs to glycerol and fatty acids under fed conditions
Under fed conditions, glycerol and fatty acids are converted to triglycerides for storage
How are lipids mobilised and processed
Lipids are mobilised and processed by lipoproteins and pancreatic hormones
What are lipoproteins
Lipoproteins are vehicles for shuttling water-insoluble lipids (fatty acids, monoglycerides, fat-soluble vitamins, and cholesterol) around the body
What are lipoproteins made up of
All made up of the same basic components; cholesterol, triglycerides, (glycero)phospholipids and proteins
Explain the funciton of Apolipoproteins
- Apolipoproteins act to stabilise and solubilise lipoprotein structures and mediate interactions with lipoprotein receptors to support lipoprotein uptake and clearance
- Apolipoproteins bind lipids to
form lipoproteins - Solubilise lipids for transport in
lymph and blood vessels
What are the 5 different Lipoproteins
From Largest to smallest:
1. Chylomicron
2. VLDL
3. IDL
4. LDL
5. HDL
What are Chylomicrons
Chylomicrons: formed in small intestine following digestion, absorbed into lymph vessels, and deliver triglycerides into bloodstream or liver
What are VLDLs
VLDLs: Very low-density lipoproteins, made in the liver from chylomicrons remnants and other liver lipids. Transport triglycerides
What are IDLs
ILDLs: Intermediate-density lipoproteins, byproducts of VLDLs (via lipoprotein lipase).
Precursor for LDLs
What are LDLs
LDLs: Low-density lipoproteins, “bad cholesterol”, byproducts of VLDL/IDL.
Transport cholesterol
What are HDLs
HDLs: High-density lipoproteins, “good cholesterol”, generated in the liver and intestines via catabolism of VLDLs and chylomicrons.
Function to reverse cholesterol transport
Explain Lipoprotine processing
Dietary fat ->
1. Chylomicrons carry triglycerides from the small intestine to the body’s cells
2. Chylomicron remnant travels to the liver for disassembly
3. VLDL produced by the liver brings more triglycerides to the body’s cells
4. VLDL becomes IDL and then cholesterol-rich LDL as triglycerides are removed
5. LDL delivers cholesterol to the body’s cells
6. HDL picks up excess cholesterol and delivers to the liver for use or disposal