Blood glucose

• What is the primary function of the glucose level maintenance system in blood?

  To regulate glucose levels for brain function
• Why is a continuous supply of glucose essential for the brain?

  Because the brain has an obligatory requirement for glucose
• What are the factors maintaining blood glucose levels?

  1. Glucose entering and leaving extracellular fluid
  2. Absorption from intestines
  3. Glycogenolysis
  4. Gluconeogenesis
  5. Hyperglycaemic hormones (glucagon, steroids)
  6. Utilization by tissues for energy
  7. Glycogen synthesis
  8. Conversion of glucose into fat (lipogenesis)
  9. Hypoglycaemic hormone (insulin)

  
• What processes contribute to the entry of glucose into the blood?

  Absorption, glycogenolysis, gluconeogenesis, hormones

  
• What factors lead to the depletion of glucose in blood?

  Utilization by tissues, glycogen synthesis, lipogenesis, insulin

  
• How is blood glucose maintained during fasting?

  By glycogenolysis and gluconeogenesis
• What alternative energy source is released by adipose tissue during fasting?

  Free fatty acids
• What happens to blood glucose levels in the postprandial state?

  • Glucose levels are high
  • Blood glucose is lowered by:
  • Tissue oxidation
  • Glycogen synthesis
  • Lipogenesis
• What is the normal fasting plasma glucose value range?

  70–100 mg/dL
• What does fasting state mean in terms of glucose estimation?

  Glucose estimated after an overnight fast
• What is the maximum glucose level after a meal in a normal person?

  140 mg/dL

  
• What is normoglycemia?

  Blood glucose within normal limits

  
• What is hyperglycemia?

  Blood glucose above the normal range

  
• What is hypoglycemia?

  Blood glucose below 50 mg/dL
• What happens to glucose in urine when blood glucose exceeds 180 mg/dL?

  Glucose appears in the urine
• What is the renal threshold for glucose?

  Blood glucose level above which glucose is excreted
• What are the types of blood glucose tests?

  • Random blood glucose
  • Fasting blood glucose
  • Postprandial blood glucose
  • Glucose tolerance test
• What is random blood glucose?

  Blood glucose analyzed at any time of day
• What is fasting blood glucose?

  Blood glucose after 12 hours fasting
• What is postprandial blood glucose?

  Blood glucose 2 hours after a meal
• What does glucose tolerance refer to?

  The ability to metabolize a glucose load
• What are the effects of insulin on blood glucose levels?

  • Lowers blood glucose
  • Promotes glycolysis
  • Favors glycogen synthesis
  • Inhibits gluconeogenesis
• What are the effects of glucagon on blood glucose levels?

  • Increases blood glucose
  • Promotes glycogenolysis
  • Depresses glycogen synthesis
  • Enhances gluconeogenesis
  • Inhibits glycolysis

  
• What are the effects of cortisol on blood glucose levels?

  • Increases blood glucose level
  • Increases gluconeogenesis
  • Releases amino acids from muscles
• What are the effects of adrenaline on blood glucose levels?

  • Increases blood glucose level
  • Promotes glycogenolysis
  • Increases gluconeogenesis
  • Favors uptake of amino acids
• What are the effects of growth hormone on blood glucose levels?

  • Increases blood glucose level
  • Decreases glycolysis
  • Mobilizes fatty acids from adipose tissue
• What is diabetes mellitus (DM)?

  A syndrome of abnormal carbohydrate metabolism
• What characterizes diabetes mellitus?

  Hyperglycemia with insulin secretion impairment
• What was the global impact of diabetes mellitus in 2017?

  Caused 4 million deaths worldwide
• What is the current treatment approach for diabetes mellitus?

  Lifestyle modification and timely medication
• What are the metabolic derangements in diabetes mellitus?

  1. Carbohydrate metabolism derangements

  • Insulin deficiency decreases glucose uptake
  • Inhibition of glycolysis and stimulation of gluconeogenesis

  1. Lipid metabolism derangements

  • High FFA levels lead to fatty liver
  • Excess acetyl-CoA diverted to ketone bodies

  1. Protein metabolism derangements

  • Increased breakdown of proteins for gluconeogenesis
• What is the fasting blood glucose level diagnostic criterion for diabetes mellitus?

  126 mg/dL or above
• What is the HbA1C diagnostic criterion for diabetes mellitus?

  6.5% or above
• What is the postprandial blood glucose diagnostic criterion for diabetes mellitus?

  200 mg/dL or above
• What is the random blood glucose diagnostic criterion for diabetes mellitus?

  200 mg/dL or above with symptoms