Week 4- Introduction to Diabetes Mellitus Flashcards
What effects does insulin have on glucose, protein and fat?
Glucose- increases muscle uptake and HGO
Protein- decrease proteolysis
Fat- decreases lypolysis and ketogensis
Where is GLUT 4 mainly found?
Myocytes (muscle) and adipocytes (fat)
What is GLUT 4?
A glucose transporter that is recruited and enhanced by insulin
What is the short term energy store?
Carbohydrates
Where are carbohydrate stores found?
Liver and muscle
What is used as an energy store after carbs run out?
Fat
What enzyme breaks down triglycerides?
Lipoprotein lipase
What hormone is needed to breakdown triglycerides?
Insulin
What is hepatic portal circulation?
Blood goes to gut then liver (smaller circulation route)- insulin can be released into this system
What effect does insulin have on ketone body synthesis?
Inhibits conversion of fatty acids to ketone bodies
What can low ketone body levels suggest about blood glucose?
Blood glucose is high as insulin is inhibiting ketone body synthesis
What is hepatic glycogenolysis?
Generation of glucose from stored glycogen in the liver
What is special about glucose in muscles?
It cannot be released only used internally
What are the 4 tests for diagnosing diabetes mellitus and what are their positive results?
Fasting glucose- >7.0 mmol/L
Random glucose- >11.1 mmol/L
Oral glucose tolerance test
HbA1c- >48 mmol/mol
Diagnosis requires 2 positive tests or 1 positive test and osmotic symptoms (polydipsia, polyuria, nocturia)
How does type 1 diabetes mellitus present?
Weight loss
Hyperglycaemia
Glycosuria with osmotic symptoms (polyuria, nocturia, polydipsia)
Ketones in blood and urine
What are useful diagnostic tests for type 1 DM?
Antibodies (GAD and IA2)
C-peptide
Presence of ketones
What happens if too much insulin is taken?
Reduced glucose output as hepatic gluconeogenesis is switched off and too much glucose uptake by muscles causing hypoglycaemia
What is impaired awareness of hypoglycaemia?
When theres reduced ability to recognize symptoms of hypoglycaemia due to loss of counterregulatory response, causes hypoglycaemia to be recurrent
What are autonomic symptoms of hypoglycaemia?
Sweating, pallor, palpitations, shaking
What are neuroglycopenic symptoms of hypoglycaemia?
Slurred speech, poor vision, confusion, seizures, loss of conciousness
What does a CBG test stand for?
Capillary blood glucose
For type 2 diabetes, where is insulin resistance mainly located?
Liver, muscle and adipose tissue
How does type 2 DM present?
Hyperglycaemia Overweight Dyslipidaemia Less osmotic symptoms Insulin resistance
What are risk factors for type 2 DM?
Age High BMI Ethnicity PCOS Family history Inactivity
Whats the medical term for feeling thirsty?
Polydipsia
Whats the medical term for frequent urination?
Polyuria
What does Hba1c show?
Glucose levels over the past few months
What distinguishes a diagnosis of T1DM from T2DM?
If they have ketone bodies in their blood this shows it is T1DM as this shows they have no insulin
What is the renal threshold for glucose reabsorbtion? What happens once this threshold is surpassed?
10 mmol/L- after this point the glucose is excreted leading to large volumes of urine
What can C peptide indicate and why?
Indicates insulin levels as one mol of c peptide gives rise to one molecule of insulin
What are the main differences between T1DM vs T2DM?
Cant produce insulin vs produce to little/dont respond to it
Sudden onset of symptoms vs gradual onset of symptoms
Must take insulin daily vs can be managed by exercise/diet/oral medication (can be treated by insulin if progresses)
What is the basal bolus regimen?
A long term insulin dose (taken by those with T1DM) to maintain long term background insulin during the day (as insulin levels in normal people are never 0)
How do patients who take insulin measure their blood glucose?
Via capillary blood glucose monitoring (NOTE: not used for diagnosis only monitoring, usually venous blood glucose is used in diagnosis)
What are capillary blood glucose readings for fasting, before meals and hypoglycaemia?
Fasting: 5-7
Before meals: 4-7
Hypoglycaemia: <4
All have units of mmol/L
What is neuroglucopenia?
When blood sugar is so low there isnt enough glucose for the brain
Why do symptoms of hypoglycaemia arise?
Due to activation of the sympathetic system
What are the effects of insulin on cell metabolism?
Promotes the breakdown of protein into gluconeogenic amino acids
Reduces the usage of oxygen
Aside from insulin, what molecules promote protein breakdown into gluconeogenic amino acids in myocytes?
Growth hormone
IGF 1
Cortisol
What effect does glucagon have on gluconeogenic amino acids?
It promotes their uptake into cells via transporters and the synthesis of proteins from them
What 2 hormones promote gluconeogensis?
Cortisol and glucagon
What hormone inhibits gluconeogenesis?
Insulin
What happens to triglyceride levels after eating?
They rise
What is the enzyme that breaks down triglycerides?
Lipoprotein lipase
What effect does insulin have on lipoprotein lipase?
It promotes its action, resulting in more non esterified fatty acids which can be carried to the liver for storage
What effect does insulin have on triglyceride synthesis? How are triglycerides synthesised?
They are synthesised from glycerol and non esterfied fatty acids, insulin promotes triglyceride synthesis
What hormones encourage breakdown of triglycerides?
Growth hormone and cortisol
What does hepatic glucose output indicate?
Levels of production of new glucose
Describe overall what happens in gluconeogensis
Glycerol is converted to glucose- it is taken into the liver via transporter and converted to gly-3P before being converted to glucose
What effect does insulin have on ketone body synthesis?
It inhibits synthesis of ketone bodies
How are ketone bodies synthesised in the liver?
Fatty acids and acyl coA are converted to acetoacetane/acetyl coA/ acetone which give rise to ketone bodies
What is hepatic glycogenolysis?
The generation of glucose from glycogen stores in the liver (NOT the synthesis of new glucose)
What is special about muscle cells glucose release?
Muscle cells cant release glucose only use it internally (so when blood glucose is low muscles stop this uptake)
What happens to glucose levels, NEFA and amino acid levels during fasting?
Glucose levels fall (3-5.5 mmol/L)
NEFA levels rise
Amino acid levels fall when fasting is prolonged
What happens to proteinolysis, lipolysis and HGO in the fasting state?
All 3 increase, HGO increases from glycogen and gluconeogensis
What happens to proteinolysis, lipolysis and HGO in the fed state?
Proteinolysis and lipolysis falls,HGO stops
What device is used to measure capillary blood glucose?
Glucose meter
What 5 hormones are released during hypoglycaemia?
Glucagon Epinephrine (adrenaline) Norepinephrine Cortisol Growth hormone
What effect does the parasympathetic nervous system have on insulin secretion?
Promotes it
What effect does the sympathetic nervous system have on insulin secretion?
Inhibits it (to increase glucose availability for fight or flight)
What is ketoacidosis?
Metabolic acidosis due to too many ketone acids in the bloodstream
