Insulin

Question 1

What do the different cells of the pancreas produce?

Answer 1

Alpha cells - glucagon
Beta cells - insulin
S cells - somatostatin
F cells - pancreatic polypeptide

Question 2

What are the actions of insulin?

Answer 2

Activates GLUT-4 gates to allow absorption of glucose by muscle and adipose.
Increase protein
Regulates glycogen synthesis.
Decreases lipolysis

Question 3

What is the natural profile of insulin secretion?

Answer 3

Basal insulin - low and steady secretion of background insulin that controls the glucose continuously released from the liver.
Meal time bolus insulin - secreted in response to glucose absorbed from food and drink

Question 4

What does glucagon do?

Answer 4

Acts via G-coupled protein receptors.
Stimulates glycogenolysis.
Stimulates gluconeogenesis.
Promotes ketogenesis.

Question 5

Why does insulin need to administered subcutaneously?

Answer 5

Inactivated by gastro-intestinal enzymes.

Question 6

What can repeated insulin injections in the same area cause?

Answer 6

Lipohypertrophy.

Question 7

What are the problems with lipohypertrophy?

Answer 7

Causes erratic absorption of insulin and poor glycaemic control.

Question 8

What are the different types of insulin replacement?

Answer 8

Short acting:
-soluble, usually given IV in DKA
- rapid-acting, faster onset (15 minutes) and shorter life (2-5 hours)
- usually injected before meals.
Intermediate acting:
- onset within 1-2 hours, lasts 11-24 hours
- may be mixed with short acting.
Long acting:
- background insulin to mimic endogenous levels
- takes 2-4 days to hit steady state
- can last 36 hours.

Question 9

What is the target HbA1c level?

Answer 9

48 mmol or lower

Question 10

How can a total daily dose of insulin for an adult be worked out?

Answer 10

0.2-0.4 units/kg/day

half basal, half bolus