Ketone Bodies and Ketosis

Question 1

When are KB metabolized, and by which tissues

Answer 1

By ALL tissue during fasting state

Question 2

Ketogenesis

Answer 2

KB synth

Acetyl CoA –> ketogenesis –> ketone bodies

Question 3

Which KB are found in blood

Answer 3

Acetoacetate (AcAc)

Beta-OH-Butyrate (BetaHB)

Question 4

Which volatile KB is exhaled

Answer 4

Acetone

Question 5

Where does ketogenesis occur

Answer 5

Liver, when glucagon:insulin is high

Question 6

HMG CoA Lyase

Answer 6

Converts HMG CoA into AcAc

Question 7

HMG CoA synthase

Answer 7

Converts acetoacetyl CoA in HMG CoA

Question 8

Mitochondrial acetyl CoA drives _____ and is high when glucagon:insulin is _____

Answer 8

drives the ketogenic enzyme activity in liver

high when glucagon:insulin is high

Question 9

Ketogenesis regulation detail

Answer 9

Glucagon stim HSL –> liver FA
Glucagon (-) ACC –> inhib FA synth, dec Malonyl CoA
Low [Malonyl CoA] –> high CPT-1 –> Acyl CoA to mitochondria
NADH from B ox inhib TCA, so acetyl CoA –> ketogenesis

Question 10

KB & muscle accessibility

Answer 10

Capillaries permeable to KB

Question 11

KB & Brain accessibility

Answer 11

Need KB transporters across BBB

Induced over >= days by high plasma [KB]

Question 12

Ketolysis main enzyme

Answer 12

Succinyl CoA transferase

takes AcAc to Acetoacetyl CoA

Question 13

Ketolysis regulation driven by _____

Answer 13

driven by [KB]

Question 14

During fasting , adipose tissue provides ____

Answer 14

FA

Question 15

During fasting, liver uses ___ & ___ products to provide ____ & ___

Answer 15

Muscle & adipose

Glucose & KB

Question 16

Can Brain use plasma FA during fasting?

Answer 16

No, FA doesn’t cross BBB