Diabetes Mellitus Flashcards
What are insulins’ major actions?
Glucose:
decrease HGO
increase muscle uptake
Protein:
decrease proteolysis
Fat:
decrease lipolysis
decrease ketogenesis
In the fasted and fed state
What is the purpose of the GLUT-4 transporter and outline its structure
Transports glucose into muscle tissue
-One side is hydrophobic
-One side is hydrophilic
What is insulins’ effect regarding GLUT-4 and roughly how much does insulin increase its uptake?
GLUT-4 is recruited and enhanced with insulin
-Has 7x the glucose uptake with insulin
What are insulins’ effects on muscle cellular metabolism?
-Enhances conversion of glucogenic amino acids(AA’s) to proteins
-Inhibits conversion of protein to AA’s
-Inhibits mitochondrial metabolism
What are insulins’ effects on hepatocytes?
-Enhances conversion of glucogenic amino acids(AA’s) to proteins
-Inhibits gluconeogenesis
Outline the usage of bodily fuel stores in terms of time to depletion, mass and energy present
Carbs are depletable within 1 day
What are the effects of insulin on adipose cells
-Promotes vascular conversion of triglycerides into NEFAs and glycerol, allowing them to be uptaken into adipocytes
-Inhibits triglyceride breakdown into glycerol+NEFAs
-Promotes conversion of glycerol+NEFAs into triglycerides from bloodstream
After a 10hr fast, what proportion of hepatic glucose output(HGO) does hepatic gluconeogenesis make up?
10%
What fuel source does the brain utilise?
(Preferred: Glucose)
Ketone bodies
Cannot use fatty acids(NEFAs)
Outline the production of ketone bodies and insulins’ influence on the process
Fatty acyl CoA/Acetyl CoA->Acetoacetate->Acetone+ 3 OH-B->Ketone bodies
Insulin reduces the conversion of fatty acyl CoA to acetoacetate
How does insulin affect glucose transport in muscle cells?
Insulin increases the uptake of glucose into the cell
What is the insulin/glucagon ratio in the fasted state?
Low ratio
How do amino acid levels and NEFA levels change in the fasted state?
NEFA levels rise
Amino acid levels drop when in a prolonged fasted state
What occurs to:
proteolysis
lipolysis
HGO from glycogenolysis and gluconeogenesis
Ketogenesis
-in the fasted state
All increase
-Ketogenesis is only active when prolonged
What responses are produced by the muscles, liver and adipocytes when insulin levels decrease?
Muscles: Increase proteinolysis
HGO: Increases glucose output
Adipocytes: Lipolysis, producing NEFAs and glycerol
What is the insulin/glucagon ratio in the fed state and what occurs to HGO, gluconeogenesis, proteolysis, glycogen stores, protein synth and lipogenesis rates?
High insulin/glucagon ratio
Decreased HGO
Decreased gluconeogenesis
Decreased proteolysis
Increased glycogen stores
Increased protein synthesis
Increased lipogenesis
How do you diagnose diabetes M through fasting glucose, random glucose and HbA1c and what conditions need to be met for a diagnosis?
Fasting glucose>7mmol/L
Random glucose>11.1mmol/L
HbA1c>48mmol/L
A diagnosis requires 2 positive tests or 1 positive test + symptoms
What is administered in an oral glucose test and what does it measure?
Fasting glucose
75g glucose load
2-hour glucose
Describe the pathophysiology of T1DM
-Autoimmune condition
-Absolute insulin deficiency
-Ketoacidosis(pH <7.3, ketones +3, HCO3- <15, gluc >11, serious acute complication of T1DM)
Why does a lack of insulin produce ketoacidosis?
Insulin inhibits conversion of fatty acyl CoA to acetoacetate, leading to progression of the ketone body pathway
What would you find in the urine of a person with T1DM?
Ketones, reducing sugars
Give some symptoms of T1DM
Weight loss
Hyperglycaemia
Glycosuria with osmotic symptoms (polyuria, nocturia, polydipsia)
Ketones in blood and urine
What are 3 useful diagnostic tests for T1DM that don’t use sugar level testing
Antibodies: GAD, IA2
C-peptide
Presence of ketones
What occurs generally to muscles and the liver with insulin induced hypoglycaemia?
Liver doesn’t secrete enough glucose
Muscles uptake too much glucose
