Lecture 10 - Diabetes Flashcards
What stimulates the release of insulin in the body?
Inc plasma glucose
Incretins like GLP1 and GIP
Parasympathetic activity (M3) receptors
What is the half life of insulin?
Short like 5mins
What inhibits the secretion of insulin in the body?
Dec plasma glucose
Cortisol
Sympathetic activity (a2 receptors)
What is the role of insulin in the body?
Reduces heptaic output of glucose by:
-inhibiting Gluconeogenesis
-inhibiting Glycogenolysis
Promotes uptake of of glucose into tissues (muscle and adipose by. Upregulating GLUT4)
Why is insulin secreted into the blood even during fasting?
Prevents receptor down regulation
What is the normally pattern of insulin release?
Biphasic pattern
What is meant by the biphasic pattern of insulin release?
Soon after eating, plasma insulin levels rapidly rise, then fall, the have a small rise again before falling
What are the 3 key clinical signs for diagnosing Type 1 diabetes Mellitus (T1DM)?
Polyuria (often wake up for the toilet iin night)
Polydipsia (thirst)
Weight loss
What are some symtpoms of Type 1 diabetes Mellitus?
Fatigue/lethary
Generalised weakness
Blurred vision
What are some classic investigation results for someone with Type 1 diabetes Mellitus?
Hyperglycaemia
Plasma or urine ketones
Elevated HbA1C
What is the difference between what plasma glucose levels and HbA1c are measuring?
Glucose = immediate measure of glucose in blood
HbA1c = perecentage of glycated haemoglobin which reflects the average blood sugar over the last 10-12 weeks
What is the biochemical triad for diabetic ketoacidosis?
(DKA)
Hyperglycaemia
Ketonaemia
Acidosis
What is the metabolic pathway for developing diabetic ketoacidosis?
Insulin normally regulates lipid metabolism by down regulating it
If insulin is absent (T1DM) then uncontrolled lipid metabolism occurs since glucose cant be moved into cells for metabolism
This leads to the lipolysis of lipids leading to production of many fatty acids protruding ketone bodies which are Acidic
What are some reasons you may suspect DKA?
Blood glucose> 11mmol/L AND:
-polyuria
-Polydipsia
-abdominal pain
-vomitting and diarrhoea
-fruity acetonic breath
-visual disturbances
What do you test for in DKA?
Ketones in urine
Blood in urine
Venous blood pH <7.3
HCO3-< 15mmol/L
What are the precipating factors for DKA?
Infection
Trauma
Non adherence to insulin treatment
Drug-drug interactions
How is DKA treated?
IV fluids
Then IV soluble insulin
The fluids correcting K+
How is human insulin made/
Recombinant DNA from bacteria or yeast
Or
Enzymatic modification of porcine
What method must insulin be administered in and why?
Paraentrally
Since insulin is a protein so needs to not be digested in the gut
What is the normally formulation for insulin?
100units/mL
With insulin resistnace and obesity can give
300 or 500units/mL
What is pharmacokinetics?
What is pharmacodynamics?
Pharmacokinetics = the ability for the drug to be absorbed and distributed in the body
Pharmacodynamics = the way that the drug works
What is the normal way that insulin is delivered?
Subcutaneous injection (can be by pump)
Like upper arms, thighs, buttocks and abdomen
When is insulin delivered via IV?
Emergencies like DKA
What are some ways that we can slow absorption of an insulin preparation?
Soluble insulin forms hexameter delaying absorption from site of injection
Insulin analogues (alter a couple amino acids to change the pharmacokinetics)
What does the site of administration of insulin injection need to be rotated?
Reduce risk of lipodystrophy
What is an example of rapid acting insulin?
Insulin aspart
What is an example of short acting insulin?
Regular soluble insulin