Metabolic and endocrine control during special circumstances

Question 1

What do anabolic hormones do?

Answer 1

Promote fuel storage

• Insulin
• Growth hormone (increases protein synthesis)

Question 2

What do catabolic hormones do?

Answer 2

Promote release from stores (glycogen, fat and muscle protein) and utilisation

• Glucagon
• Adrenaline
• Cortisol
• Growth hormone
• Thyroid hormone

Question 3

What does insulin inhibit?

Answer 3

• Gluconeogenesis
• Glycogenolysis
• Lipolysis
• Ketogenesis
• Proteolysis

Question 4

What does insulin stimulate?

Answer 4

• Glucose uptake in muscle and adipose (GLUT 4)
• Glycolysis
• Glycogen synthesis
• Protein synthesis

Question 5

Describe what happens in energy starvation

Answer 5

1) Glucagon and cortisol release
2) Decrease in insulin and anti-insulin effects of cortisol prevent most cells from using glucose (fatty acids preferred)
3) Liver starts to produce ketone bodies
4) Fat stores deplete and protein used as fuel
5) Death from loss of muscle mass (respiratory infection)

Question 6

Describe what happens in the anabolic phase in pregnancy

Answer 6

The first half (20 weeks) of pregnancy

• Increase in maternal fat stores
• Small increase in level of insulin sensitivity

Question 7

What is the importance of the anabolic phase in pregnancy?

Answer 7

Nutrients storage to meet future demands of rapid foetal growth in late gestation and lactation after birth

Question 8

Describe what happens in the catabolic phase in pregnancy?

Answer 8

The second half of pregnancy

• Decreased insulin sensitivity (increased resistance)
• Increase in maternal glucose and free fatty acids

Question 9

What is the importance of the catabolic phase in pregnancy?

Answer 9

Maternal metabolism adapts to meet an increasing demand by foetal-placental unit

Question 10

Why is the foetus described as an aggressive parasite?

Answer 10

Foetus controls the maternal metabolism to ensure its own survival

Question 11

What is the foetoplacental unit?

Answer 11

A new endocrine entity made by placenta, foetal adrenal glands and foetal liver

Question 12

What does the placenta secrete and what is the effect of these?

Answer 12

Wide range of hormones that controls maternal hypothalamic pituitary axis

• CRH
• GnRH
• TRH
• GHRH
• ACTH
• hCG

Question 13

What are the two important steroid hormones produced by the placenta?

Answer 13

Oestriol and progesterone

Question 14

What are examples of anti-insulin hormones?

Answer 14

• Corticotrophin releasing hormone
• Human placental lactogen
• Progestrerone

Question 15

What are the effects of anti-insulin hormones?

Answer 15

• Transient hyperglycaemia after meals (from increased insulin resistance)
• Hypoglycaemia can occur between meals and at night because of continuous foetal draw of glucose