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26 Cards in this Set
- Front
- Back
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FA synthesis
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use the SYtrate shuttle
Acetyl-CoA ----ACC--> malonyl-CoA --> FA synthesis ***Rate limiting: Acetyl CoA Carboxylase |
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FA degradation
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CARnage of FA
FA + CoA ---> (with FA CoA synthetase) Acyl-CoA ----> (with acyl-CoA DH) beta-oxidation to acetyl-CoA for ketone bodies and TCA rate-limiting: carnitine acyltransferase (Carnitine shuttle) |
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Carnitine deficiency
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can't transport LCFAs into mitochondria -->toxic accum
weakness, hypotonia, hypoketotic hypoglycemia |
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Acyl-CoA DH def
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increase dicarboxylic acids, decrease glucose and ketones
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Ketones
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In liver, FA and AA are metabolized into:
Acetoacetate (some will convert to acetone) Beta-hydroxybutyrate (used in muscle and brain) Starvation: oxaloacetate depleted for GNG Alcoholism: excess NADH shunts oxaloacetate to malate result: TCA stalled --> shunt glucose and FFA toward ketogenesis rate: HMG-CoA synthase |
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Fed state
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glycolysis and aerobic respiration
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Fasting
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Hepatic glycogenolysis
hepatic GNG adipose release of FFA |
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Starvation 1-3days
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1. Hepatic glycogenolysis (depleted after 1 day)
2. Adipose release of FFA 3. Muscle and liver, shift fuel use from glucose to FFA 4. Hepatic GNG (lactate, alanine, adipose glycerol & propionyl-CoA (OCFA) |
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Starvation >3days
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Adipose stores: ketones main energy for brain and heart
after depleted: vital protein degradation --> organ failure and eath |
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Lecithin-cholesterol acyltransferase (LCAT)
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catalyzes esterification of cholesterol (2/3)
ex: nascent HDL --> Mature HDL |
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Cholesterol ester transfer protein (CETP)
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mediates transfer of cholesterol esters to other lipoprotein particles
-Allows HDL to deposit chol onto VLDL, IDL, LDL |
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A-I
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Activates lcAt, which catalyzes esterification of cholesterol (nascent HDL --> mature HDL)
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B-100
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Binds to LDL receptor, mediates VLDL secretion
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C-II
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C-LL
Cofactor for LPL |
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B-48
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Mediates chylomicron secretion
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E
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Mediates Extra (remnant) uptake
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C-III
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inhibits LPL
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LDL
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transports chol from liver to tissues:
formed by LPL modification of VLDL in peripheral tissue -taken up by target cells via receptor-mediated endocytosis apolipoproteins: B-100 |
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HDL
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transports chol from periphery to liver
-repository for apoC and apoE (needed for chylomicron and VLDL metabolism -secreted from liver and intestine |
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Chylomicron
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-delivers dietary TGs to peripheral tissue
-delivers chol to liver in the form of chylomicron remnants (mostly depleted of their triacylglycerols) -secreted by intestinal epithelial cells apolipoproteins: B-48, A-IV, C-II, E |
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VLDL
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delivers hepatic TGs to peripheral tissue; secreted by liver
apolipoproteins: B-100, C-II, E |
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IDL
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formed in degardation of VLDL
-delivers TGs and chol to liver, where they are degraded to LDL apolipoproteins: B-100, E |
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Type I: hyperchylomicronemia
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Increased chylomicrons
elevated TG, chol LPL def or altered apo C-II (cofactor for LPL) causes pancreatitis, HSM, eruptive/pruritic xanthomas (no increased risk for atherosclerosis) |
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Type IIa: familial hypercholesterolemia
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Auto dom
increased LDL elevated cholesterol **absent or decreased LDL receptors causes accel atherosclerosis, tendon xanthomas, corneal arcus |
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Type IV: hypertriglyceridemia
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increased VLDL
elevated TG due to hepatic overproduction of VLDL causes pancreatitis |
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Abetalipoproteinemia
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inability to synthesie lipoproteins due to def in apoB-100 and apoB-48
sxs in first few months of life; FTT, steatorrhea, acanthocytosis (vit E), ataxia (vit E), night blindness (vit A) bx shows accum of lipids within enterocytes; can't secrete chylomicrons Tx: vit E (bc of def and helps restore lipoproteins); TG restriction |
