Treating Diabetes Flashcards
Where is insulin produced?
In beta cells of the pancreas within the islets of langerhans.
How is insulin released from beta cells?
Beta cells have ATP sensitive ATP channels. When glucose arrives at the cell it enters the cell via a GLUT 2 transporter. It then undergoes glycolysis which produces ATP. This activates the sulphonylurea receptor subunit of the potassium channel which closes it so depolarises the cell. This causes opening of L type calcium channels which leads to exocytosis of insulin vesicles.
How is insulin taken up into peripheries?
Peripheral tissues express specific cell surface insulin receptors linked to tyrosine kinase. This leads to translocation of GLUT 4 transporter to cell surface membrane allowing glucose uptake.
How does insulin affect its target cells?
Inhibition of gluconeogenesis and glycogenolysis
Stimulates uptake of glucose into liver, muscle and adipose
Promotes uptake of fats.
What are the categories of insulin analogues?
Give a brief time period that each one acts for
Ultrafast acting- within mins, short duration of action
Rapid acting eg humalog, novarapid- 5-15 mins, injected just before eating
Short acting- actrapid, humulin S- starts to work after 30-60 mins. Need to inject 15-30 mins before eating.
Intermediate acting- onset 2-4 hours. Lasts much longer
Long acting
Very long acting- onset after 2-6 hours. Lasts up to 24 hours.
What is the first line of treatment in type II diabetics?
Lifestyle and dietary modifications as well as close monitoring of blood glucose.
Eg weight reduction
Regular exercise
Reduce energy intake
Avoid sucrose and alcohol.
What is the fasting plasma glucose threshold for diagnosing diabetes?
7mmol/L or higher
What is the aim HbA1c level in early stages of type II diabetes therapy?
48mmol per mol
If diet and lifestyle changes do not work in reducing blood sugar in type II diabetes which pharmacological treatment is needed?
Metformin
+ sulfonylurea if this doesnt work.
+pioglitazone if this doesnt work
Eventually exogenous insulin will be needed
What are the side effects of taking insulin?
Hyper+ hypoglycaemia
Lipodystrophy, lipohypertrophy or lipoatrophy
Painful infections
Sometimes insulin allergies.
What is the mechanism of action of metformin?
Decreases insulin resistance and decreases hepatic glucose production
Does metformin cause weight gain?
No it is relatively weight neutral
What are the side effects of taking metformin?
Mainly Gi symptoms. Lactic acidosis is rare.
