INSULIN, GLUCAGON AND ADRENALINE

• EFFECT OF INSULIN?

  1. Insulin (1st messenger) binds to complementary insulin receptor
  2. Activates tyrosine kinase
  3. Stimulate glucose transporter protein (GLUT4 protein) vesicles to fuse with cell-surface membrane
  4. GLUT4 inserted into cell-surface membrane
  5. Glucose in blood enters by facilitated diffusion down concentration gradient
  6. Glucose either
  7. Is converted to glycogen via glycogenesis
  8. Stored as lipids
  9. Used in increased respiration
  10. Required to maintain concentration gradient
  11. Blood glucose concentration lowers and returns to normal (negative feedback)
• EFFECT OF GLUCAGON?

  1. Glucagon (1st messenger) binds to complementary glucagon receptor
  2. Activates adenyl cyclase
  3. Causes ATP to be converted into cAMP (2nd messenger)
  4. Stimulates phosphorylation of enzymes to activate them, e.g. protein kinase A
  5. Causes cascade of enzyme reactions
  6. Glycogen is converted to glucose via glycogenolysis
  7. Glycerol and AAs are converted into glucose via gluconeogenesis
  8. Glucose moves out down concentration gradient by facilitated diffusion
  9. Blood glucose concentration increases and returns to normal (negative feedback)
• EFFECT OF ADRENALINE?

  • 1st messenger
  • same response as glucagon
  • causes glycogenolysis
  • but does not cause gluconeogenesis
  • different complementary protein receptors
• WHAT DOES cAMP STAND FOR?

  cyclic AMP
• WHERE DO THE EFFECTS OF INSULIN, GLUCAGON AND ADRENALINE OCCUR?

  liver/ muscle cells