Ketosis

General: Acetyl CoA can go to Krebs, Acetoacetate (then to acetone), or b -hydroxybutyrate.

Clinical Signs:

High blood ketone level

High urine ketone level

Low blood glucose

Breath smells like acetone, filtered through lungs

Causes:

1) body is dependant on gluconeogenesis (depletes OAA)

2) body mobilizing stored fat (b -oxidation ® increase acetyl-CoA)

3) Acetyl-CoA ® ketone bodies

When it occurs

1) starvation

2) high producing dairy cow (lactose - glu + gal), (no glu absorbed (glu)), (energy deficient - body fat - acetyl-CoA)

3) Late pregnant ewe with twins or triplets. Uterus increase - push against rumen, decrease DMI

Blood Changes: assume dairy cow

Component

Normal

Ketosis

Glucose

52

28

Ketone

3

41

FFA

3

33

Treatment:

­ OAA precursors - enter Krebs as

- propionate - succinyl-CoA

- glutamate - a -ketogluterate

- aspartate - OAA

 

Fatty Acid Synthesis

General: really - but apparently

Quassi - reverse b -oxidation

CHO (AA, VFA)- get acetyl-CoA - add 2 at time - get FA

1st one = 2C, then rest enter as malonyl-CoA (3C)

Acetyl-CoA + CO2 - malonyl-CoA

Basic Take-Home Points:

1. Addition of malonyl-CoA to acetyl-CoA (Acyl-CoA)

2. For every malonyl-CoA formed - you need:

1 ATP

2 NADPH

biotin & CO2

Example:

Palmitic Acid (16:0)

8 acetyl-CoA + 7 ATP + 14 NADPH ® palmitic acid + 8 CoASH + 14 NADP + 7 ADP

Body can synthesize FA of 18C or less