Lipids Part 1 continued Flashcards
What does insulin do when glucose levels rise?
Inhibit adenylate cyclase and inhibit process of lipolysis
What are the two major fates of fatty acids?
- oxidation- energy source for liver - production of ketone bodies
- triacylglycerol (TG or lipid) formation- local store for liver energy needs- distributed to other tissues as VLDL
Effects of Carnitine palmitoyl-transferase deficiency (or CPT-1a or CPT-2)?
No b-oxidation, hypoglycemia
Why do you get hypoglycemia?
normally when start fasting- start using lipids as energy store but if can’t get into mitochondria to oxidize, can’t get energy from lipids. And will be reliant on glucose all the time for energy production. Won’t be able to maintain blood glucose levels
Describe Beta oxidation in peroxisomes?
Very-long chain fatty acids >22 carbons undergo a preliminary b-oxidation in peroxisomes.
First step does not produce FADH2 and so less energy efficient
The shortened FA linked to carnitine diffuses from peroxisome into the mitochondria for further oxidation.
Defects in this pathway results in VLC-FA accumulation in blood and tissue
Why can’t we convert acetyl coA into glucose?
-no fatty acid is gluconeogenic
Cannot convert acetyl CoA into glucose due to thermodynamically irreversible pyruvate to acetyl CoA step- (Important)
Describe characteristics of ketone bodies?
-normal metabolites of fat
-normal energy sources to use when fasting
How are ketone bodies produced?
- need energy source you can transport around body and use elsewhere
-used in skeletal muscle and in brain for providing energy
Where do we get fatty acids from?
Diet (essential fatty acids)
Stored lipid/triglyceride (released from adipose tissue)
Synthesis – (via palmitate generated from acetyl CoA)
Where does fatty acid synthesis occur in?
liver , lactating mammary gland, adipose tissue
