Hormones and metabolism

Question 1

What is the influence of insulin on the absorptive phase on macronutrients in the liver, fat and muscle?

Answer 1

Carbs - promotes uptake of glucose from blood by hepatocytes, adipose tissue and skeletal muscle cells and encourages glycogenesis
Fats:
- insulin inhibits lipolysis in the liver (reducing ketone bodies)
- promotes fat storage in fat cells by reducing release of fatty acids into blood to encourage fat cells to take up and store triglycerides
Proteins:
- encourages protein synthesis by promoting uptake of amino acids

Question 2

What is the effect of insulin in the inter-prandial (post-absorptive) phase on macronutrients in liver, fat and muscle?

Answer 2

Carbs:
- insulin secretion decreases
- liver releases more glucose into bloodstream to help maintain sugar levels
- in fat and muscle uptake of glucose for energy is decreased
- adipose tissue release fatty acids into bloodstream
Fats:
- increases lipolysis in liver and fat cells
- more fatty acids in bloodstream
Proteins:
- liver converts amino acids into glucose via gluconeogenesis
- muscle protein breakdown to provide amino acids for energy production

Question 3

What is gluconeogenesis?

Answer 3

the synthesis of new glucose molecules from non-carbohydrate precursors, such as amino acids, glycerol and lactate