Biochemistry of Fed/Starved States

Question 1

How much glucose is used (consumed) under different conditions, and where is it coming from?

Question 2

Compare Phase I (very well fed state) to Phase V (starved 5 weeks)

Answer 2

Insulin/glucagon ratio is 1/10th in starvation state (0.5 [high] –> 0.05)

Glucose levels decreased ~20-30%

Fatty acids increased x10

Ketone bodies increased x100

Substrates for gluconeogenesis (lactate, pyruvate, alanine) go down significantly (~80%) because are being used efficiently for gluconeogenesis

ATP equivalents ‘circulating in blood’ - actually a calculated value of energy available from circulating fuel (not actual ATP circulating in blood)

Question 3

Describe tissue interactions in the FED STATE

Answer 3

Insulin/glucagon ratio is HIGH

Glucose is used heavily for: synthesis & storage [glycogen & fat]

Question 4

Describe tissue interactions in the STARVED STATE (i.e. Phases IV & V)

Answer 4

Insulin/glucagon ratio is LOW

Doing GNG (from amino acids, pyruvate, lactate, glycerol) - to maintain glucose

Ketone body synthesis increases - NOT causing ketoacidosis

Question 5

Draw out the Molecular Mechanism of Hormonal Control of the Liver in the FED STATE

Answer 5

Insulin

Question 6

Draw out the Molecular Mechanism of Hormonal Control of the Liver in the STARVED (FASTING) STATE

Answer 6

Glucagon