BIOLOGY 2D03 Lecture Notes - Insulin Resistance, Thiolysis, Succinyl-Coa
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KETOGENESIS
B-OH-Butyrate reduced to Acetoacetate (AcAc)
ratio determined by NADH/NAD in liver mito
**only in liver mito (where B-oxidation occurs**
some acetate decarbed to acetone
conditions:
high fat (ketogenic) diet
fasting/starvation
prolonged exercise
diabetes (I)
fasting does not affect amt of glucose in blood
possible b/c alternate fuel utilization (80-fold inc in BHB)
changes during starvation
- brain shifts to ketone utilization to spare muscle
glucose still used, but not fully oxidized (to save it)
- LESS muscle breakdown
“sparing effect” due to ketogenesis
ACAC SYNTH: HMG-CoA CYCLE
1) THIOLASE: 2 X AcetylCoA AcAcCoA + CoA (Thiolase INHIBITOR)
2) HMG-COA SYNTHASE: AcAc-CoA + acetyl-CoA HMG-CoA
(4C) (2C) (6C)
SH-CoA is lost from Acetyl CoA and INHIBITS SYNTHASE
2) HMG COA LYASE: HMG-CoA AcAc + AcetylCoA
(used in step 2)