L13 - Drug treatments for diabetes

Question 1

Describe the release of insulin

Answer 1

Biphasic

Question 2

What happens in phase 1 of insulin release?

Answer 2

Brief spike in insulin

• Promotes peripheral utilisation of the prandial nutrient load
• Suppresses hepatic glc prod
• Limits postprandial glc elevation
• Release of preformed insulin from storage granules within the beta cells
• Lasting approx 10 min

Question 3

What happens in phase 2 of insulin release?

Answer 3

Prolonged phase of insulin release

• Response to glc entering bloodstream
• Reaches plateau at 2-3h

Question 4

Describe the structure of the insulin receptor

Answer 4

1. 2 alpha subunits
   - Extracellular (binding site)
2. 2 beta subunits
   - Transmembrane (tyrosine kinase)

Question 5

What is type 1 diabetes?

Answer 5

• Inc glc
• Young
• 10% of diabetics
• Genetic
• AID (possible from viral infection)
• Resulting in beta cell loss

Question 6

What are the available treatments for type 1 diabetes?

Answer 6

Pre-diabetic:

• Possible vaccine?
• Nicotinamide (DNA repair)
• Diet + insulin (+ metformin if BMI >25)

Question 7

What is type 2 diabetes?

Answer 7

• Obesity
• No major loss of beta cells
• Insufficient inc in basal insulin in blood
• Loss of 1st phase of insulin secretion
• Insulin resistance; (possible dysfunction of IRS proteins)

Question 8

What are the available treatments for type 2 diabetes?

Answer 8

• Diet/ exercise
• Drugs
• ACE inhibitors
• Statins
• May need insulin

Question 9

What is the mechanism of metformin?

Answer 9

Requires insulin
In the liver/ muscle:
- Dec gluconeogenesis in liver via activation of AMP-activated protein kinase –> dec gene expression
- Inc glc uptake in muscle

Question 10

What are the possible side effects of metformin?

Answer 10

• No hypoglycaemia
• No inc appetite
• Lactic acidosis

Question 11

What is metformin used for?

Answer 11

• For obese diabetics

- Combination therapy