Diabetes

Question 1

What are the 4 ways that insulin decreases blood glucose?

Answer 1

• incr. glucose uptake into muscle and fat cells
• incr. glycogen synthesis
• dec. gluconeogenesis
• dec. glycogen breakdown

Question 2

Glucagon stimulates what 3 mechanisms?

Answer 2

• gluconeogenesis
• glycogenolysis
• lipolysis

Question 3

Beta cells respond to which two stimuli?

Answer 3

absolute glucose concentration

rate of change of blood glucose

Question 4

Responding to a change in blood glucose has 2 phases which are?

Answer 4

1. Initial rapid phase (release of stored hormone)

2. Slower delayed phase (continued release of stored hormone and NEW synthesis).

Question 5

How is insulin secreted?

Answer 5

ATP-sensitive K+ channels determine the resting membrane potential in B-cells.

Glucose enters B-cells via GLUT-2

Glucose metabolised by glucokinase and glycolysis increases intracellular ATP.

Incr. ATP blocks K(ATP) channels causing depolarisation, CA2+ channels open.

Ca2+ signal induces insulin secretion.

Question 6

Insulin receptor is what kind of receptor?

Answer 6

Tyrosine kinase receptor. When insulin binds, it leads to phosphorlylation.

Question 7

Diabetes effects what % of the population?

Answer 7

3-5%

Question 8

The degeneration of B-cells is what type of diabetes?

Answer 8

Type 1

Question 9

What % of diabetes is Type 1?

Answer 9

15-20%

Question 10

What main 2 conditions can result from low insulin?

Answer 10

Hyperglycaemia

• liver/skeletal muscle can’t store glycogen
• Tissues unable to take up and use glucose

Ketosis

• inhibition of FA synthesis
• ketones form (metabolic acidosis)
• aceto-acetate forms
• B-hydroxybutyrate
• acetone

Question 11

What was wrong using pork or beef insulin to treat IDDM?

Answer 11

Poorly tolerated by many patients and different aa in peptide chains

Question 12

What is Humulin?

Answer 12

Human insulin. This is genetically engineered and better tolerated.

Question 13

3 ways insulin can be injected?

Answer 13

Sub-cutaneously
Jet-injection
Pump

Question 14

What is the most fast acting type of injectable insulin?

Answer 14

Humalog (acts in 45-90min, stops after 3-4 hrs)

Question 15

What is the fast acting/regular type of injectable insulin?

Answer 15

Humulin (acts in 2-5 hrs, stops after 5-8 hrs)

Question 16

What is the intermediate acting injectable type of insulin?

Answer 16

NPH/Lente (acts in 6-12 hrs, stops 20-24 hrs)

Question 17

What is a long acting insulin type?

Answer 17

Ultralente (prolongs entry of insulin into blood stream for 4-6 hrs, stops after 28 hrs)

Question 18

What is an ultra-long acting insulin type?

Answer 18

Glargine (constant rate for 24 hrs)

Question 19

Which type of Diabetes is autoimmune?

Answer 19

Type 1

Question 20

When does NIDDM develop?

Answer 20

After 35 years of age

Question 21

What does NOT form in type 2 diabetes?

Answer 21

Ketosis

Question 22

What is type 2 diabetes due to?

Answer 22

Insensitivity of target cells to insulin.

Question 23

What 2 factors causes insulin resistance?

Answer 23

Reduced number of insulin receptors

Problem in pathway of insulin action.

Question 24

What is used to treat type 2 diabetes?

Answer 24

Oral hypoglycaemic agents

• sulfonylureas
• meglinitides
• Biguanides

Question 25

How do sulfonylureas increase the release of insulin in type 2 diabetes?

Answer 25

high affinity for sulfonylureas on K(ATP) channels

Block K(ATP) channels

Depolarisation in the cells

Incr. insulin release

Question 26

How do meglinitides increase the release of insulin in type 2 diabetes?

Answer 26

Work on the pancreas to promote insulin secretion

Same as sulfonylureas, except different binding site.

Question 27

How do biguanides increase the release of insulin in type 2 diabetes?

Answer 27

Reduces liver gluconeogenesis

Activates AMP-activated protein kinase

Incr. glucose uptake and utilisation