Week 8 - Diabetes mellitus and The Endocrine Pancreas

Question 1

How do sulphonylureas reduce blood glucose?

Answer 1

These are oral hypoglycaemic agents that stimulate insulin release from beta cells.

Question 2

Describe the mode of action of metformin in the treatment of diabetes.

Answer 2

Biguanide that increases insulin sensitivity: increases glucose uptake, reduces gluconeogenesis and increases glycogen synthesis.

Question 3

Outline how insulin is secreted from beta cells.

Answer 3

The secretion of insulin is predominantly dependent on circulating glucose levels.
High glucose increases ATP production, which causes ATP-sensitive K+ channels to close and results in depolarisation of beta cells.
This activates voltage-gated calcium channels.
Entry of calcium causes the exocytosis of vesicles containing insulin.