Glucose-alanine cycle

Question 1

During fed state what happens to amino acids?

Answer 1

Metabolised into glucose, glycogen, fatty acids
Oxidised generate ATP

Question 2

Fed state is amino acid uptake anabolic or catabolic?

Answer 2

Anabolic

Question 3

Fasting state is amino acid anabolic or catabolic?

Answer 3

Catabolic

Question 4

What 2 hormones stimulate gluconeogenesis?

Answer 4

Glucagon
Cortisol

Question 5

Outline Glucose-Alanine cycle?

Answer 5

1) Alanine transported in blood into hepatocyte
2a) Alanine deamination form pyruvate (loses NH4+) donates amino group
2b) Alpha ketoglutarate undergoes transamination to glutamate (gains NH4+ from alanine)- catalysed by alanine aminotransferase (ALT)
3) Amino group of glutamate enters urea cycle- used as nitrogen donor- forms urea
4) Pyruvate undergoes gluconeogenesis form glucose
5) Glucose travels through blood
6) Glucose taken up by muscle cells- undergo glycolysis to form pyruvate
7a) Glutamate deaminated to a-Ketoglutarate- loses amino group (deamination)
7b) Gives amino group to pyruvate- pyruvate converted alanine (transamination)
8) Alanine transported to blood to hepatocyte

Question 6

When does glucose-alanine cycle occur?

Answer 6

Fasting state

Question 7

Draw glucose-alanine cycle?

Answer 7

Question 8

Pyruvate never NH4
Alanine always NH4

Glutamate always NH4
A Ketoglutamate never

Losing NH4- deamination
Gaining NH4- transamination

Pyruvate to alanine in muscle
Alanine to pyruvate in hepatocyte

Answer 8

Pyruvate never NH4
Alanine always NH4

Glutamate always NH4
A Ketoglutamate never

Losing NH4- deamination
Gaining NH4- transamination

Pyruvate to alanine in muscle
Alanine to pyruvate in hepatocyte

Question 9

What is gluconeogenesis?

Answer 9

Pyruvate to glucose

Question 10

What is glycolysis?

Answer 10

Glucose to pyruvate

Question 11

What is purpose glucose-alanine cycle?

Answer 11

Move ammonia from muscle to liver as alanine
In liver alanine makes pyruvate (starting block gluconeogenesis)
Release ammonia conversion into urea
Energetic burden gluconeogenesis imposed on liver rather than muscle
Muscle ATP is devoted to muscle contraction