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Gluconeogenesis Suggested Reading: Lippincot’s Ilustrated reviews: Biochemistry

Gluconeogenesis - JU Medicine · ≈ 75 g ( liver glycogen); enough for 16 hours ≈ 400 g (muscle glycogen); for muscle use only Main source of energy for resting muscle in postabsobtive

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Page 1: Gluconeogenesis - JU Medicine · ≈ 75 g ( liver glycogen); enough for 16 hours ≈ 400 g (muscle glycogen); for muscle use only Main source of energy for resting muscle in postabsobtive

Gluconeogenesis

• Suggested Reading:

• Lippincot’s Ilustrated reviews: Biochemistry

Page 2: Gluconeogenesis - JU Medicine · ≈ 75 g ( liver glycogen); enough for 16 hours ≈ 400 g (muscle glycogen); for muscle use only Main source of energy for resting muscle in postabsobtive

Glucose Synthesis is Required for Survival

• Brain is dependent on glucose 120g/day

• Body glucose reserve is limited≈ 20 g (extra cellular fluid)

≈ 75 g ( liver glycogen); enough for 16 hours

≈ 400 g (muscle glycogen); for muscle use only

Main source of energy for resting muscle in postabsobtivestate is fatty acids. 80% of glucose is used by brain & rbc

• 70 Kg man has ≈ 15 Kg fat – Fatty acids can not be converted to glucose

– Utilization of FA is increased 4-5 X in prolonged fasting

– In prolonged fasting; FA ketone bodies at high rate

Page 3: Gluconeogenesis - JU Medicine · ≈ 75 g ( liver glycogen); enough for 16 hours ≈ 400 g (muscle glycogen); for muscle use only Main source of energy for resting muscle in postabsobtive

Gluconeogenesis occurs mainly in the liver

Tissues that do not oxidize glc. completelye.g RBCExcercising muscle

Muscle A.Acids

Adipose tissue

Lactate

alanine

glycerol

Glucose

Peripheral tissues

Page 4: Gluconeogenesis - JU Medicine · ≈ 75 g ( liver glycogen); enough for 16 hours ≈ 400 g (muscle glycogen); for muscle use only Main source of energy for resting muscle in postabsobtive

Lactate Pyruvate Amino acids

Amino acids oxaloacetate propionate

Glycerol Triosephosphates Fructose

Galactose Glucose

Page 5: Gluconeogenesis - JU Medicine · ≈ 75 g ( liver glycogen); enough for 16 hours ≈ 400 g (muscle glycogen); for muscle use only Main source of energy for resting muscle in postabsobtive

Glucose

Glucose 6-phosphate

Fructose 1,6- bisphosphate

2 Phosphoenolpyruvate

Oxaloacetate

2 Pyruvate

Fructose 6-phosphate

Page 6: Gluconeogenesis - JU Medicine · ≈ 75 g ( liver glycogen); enough for 16 hours ≈ 400 g (muscle glycogen); for muscle use only Main source of energy for resting muscle in postabsobtive
Page 7: Gluconeogenesis - JU Medicine · ≈ 75 g ( liver glycogen); enough for 16 hours ≈ 400 g (muscle glycogen); for muscle use only Main source of energy for resting muscle in postabsobtive

Carboxylation of Pyruvate Produces Oxaloacetate

ADPATP >CO2

Page 8: Gluconeogenesis - JU Medicine · ≈ 75 g ( liver glycogen); enough for 16 hours ≈ 400 g (muscle glycogen); for muscle use only Main source of energy for resting muscle in postabsobtive
Page 9: Gluconeogenesis - JU Medicine · ≈ 75 g ( liver glycogen); enough for 16 hours ≈ 400 g (muscle glycogen); for muscle use only Main source of energy for resting muscle in postabsobtive
Page 10: Gluconeogenesis - JU Medicine · ≈ 75 g ( liver glycogen); enough for 16 hours ≈ 400 g (muscle glycogen); for muscle use only Main source of energy for resting muscle in postabsobtive
Page 11: Gluconeogenesis - JU Medicine · ≈ 75 g ( liver glycogen); enough for 16 hours ≈ 400 g (muscle glycogen); for muscle use only Main source of energy for resting muscle in postabsobtive

Formation and Hydrolysis of Glucose 6-phosphate

Glc. + Pi Glc. 6-phosphate + H2O ΔG = +veATP + H2O ADP + Pi ΔG = -ve

Glc. + ATP Glc. 6-phosphate + ADP ΔG = -ve

Glc. 6-phosphate + H2O Glc. + Pi ΔG = -ve

HK

Phosphatase

Page 12: Gluconeogenesis - JU Medicine · ≈ 75 g ( liver glycogen); enough for 16 hours ≈ 400 g (muscle glycogen); for muscle use only Main source of energy for resting muscle in postabsobtive

Glucose

Glucose 6-phosphate

Fructose 1,6- bisphosphate

2 Phosphoenolpyruvate

Oxaloacetate

2 Pyruvate

Fructose 6-phosphate

ATP

GTP

ATP X 2

X 2

X 2

Page 13: Gluconeogenesis - JU Medicine · ≈ 75 g ( liver glycogen); enough for 16 hours ≈ 400 g (muscle glycogen); for muscle use only Main source of energy for resting muscle in postabsobtive

T

2 ADP2 ATP

Page 14: Gluconeogenesis - JU Medicine · ≈ 75 g ( liver glycogen); enough for 16 hours ≈ 400 g (muscle glycogen); for muscle use only Main source of energy for resting muscle in postabsobtive
Page 15: Gluconeogenesis - JU Medicine · ≈ 75 g ( liver glycogen); enough for 16 hours ≈ 400 g (muscle glycogen); for muscle use only Main source of energy for resting muscle in postabsobtive

The Cori Cycle

Page 16: Gluconeogenesis - JU Medicine · ≈ 75 g ( liver glycogen); enough for 16 hours ≈ 400 g (muscle glycogen); for muscle use only Main source of energy for resting muscle in postabsobtive
Page 17: Gluconeogenesis - JU Medicine · ≈ 75 g ( liver glycogen); enough for 16 hours ≈ 400 g (muscle glycogen); for muscle use only Main source of energy for resting muscle in postabsobtive

PFK

Page 18: Gluconeogenesis - JU Medicine · ≈ 75 g ( liver glycogen); enough for 16 hours ≈ 400 g (muscle glycogen); for muscle use only Main source of energy for resting muscle in postabsobtive
Page 19: Gluconeogenesis - JU Medicine · ≈ 75 g ( liver glycogen); enough for 16 hours ≈ 400 g (muscle glycogen); for muscle use only Main source of energy for resting muscle in postabsobtive

Pyruvate kinase

Pyruvate carboxylase

Page 20: Gluconeogenesis - JU Medicine · ≈ 75 g ( liver glycogen); enough for 16 hours ≈ 400 g (muscle glycogen); for muscle use only Main source of energy for resting muscle in postabsobtive
Page 21: Gluconeogenesis - JU Medicine · ≈ 75 g ( liver glycogen); enough for 16 hours ≈ 400 g (muscle glycogen); for muscle use only Main source of energy for resting muscle in postabsobtive
Page 22: Gluconeogenesis - JU Medicine · ≈ 75 g ( liver glycogen); enough for 16 hours ≈ 400 g (muscle glycogen); for muscle use only Main source of energy for resting muscle in postabsobtive
Page 23: Gluconeogenesis - JU Medicine · ≈ 75 g ( liver glycogen); enough for 16 hours ≈ 400 g (muscle glycogen); for muscle use only Main source of energy for resting muscle in postabsobtive

Next topic: Glycogen Metabolism

Page 24: Gluconeogenesis - JU Medicine · ≈ 75 g ( liver glycogen); enough for 16 hours ≈ 400 g (muscle glycogen); for muscle use only Main source of energy for resting muscle in postabsobtive