Topic 72 - Classification of hormones, dynamics of the ligand - receptor interaction, the feed-back mechanism

Question 1

Words to include in classification of hormones

Answer 1

• Steroids
• Iodothyrenes
• Clacitrol
• Peptide hormones
• Catecholamines
• Hydrophilic
  
  • Lipid-insoluble hormones
• Lipophilic
  
  • Lipid soluble hormones
• Binding protein / carrier protein
• Half life
• IC receptor
• Membrane receptor / surface receptor
• IC mediator
• Receptor-hormone complex
• Second messenger
  
  • cAMP
  • cGMP
  • Calcium ions
  • Diacylglycerol (DAG)
  • Inositol triphosphate (IP3)
• Plasma membrane
• Nuclear envelope
• Gene expression

Question 2

Words to include in dynamics of the ligand-receptor interaction

Answer 2

• In vitro
  
  • Scatchard
  • Molecules
  • Proteins
  • Ligand
  • Large-molecular binding site (receptor)
• In vivo
  
  • Radio-labeled hormone
  • Circulation
• Scatchard analysis
  
  • Ligand-receptor interaction
  • Binding sites (Bmax)
  • Dissocitation constant of the binding sites (Kd)
  • Affinity of binding
  • Bound hormone
  • Bound / free hormone ratio
  • Non-labeled ligand
  • Non-labeled hormone
  • Radioactive hormone

Question 3

Words to include in the feedback mechanism

Answer 3

• Hormone production
• Inhibited
• Concentration
• Long feedback
  
  • Peripheral gland
  • Hypothalamus
• Short feedback
  
  • Peripheral gland
  • Pituitary gland
• Ultra-short feedback
  
  • Hypothalamus
  • Pituitary gland

Question 4

Classification of hormones

Answer 4

Question 5

Dynamics of the ligand-receptor interaction

Answer 5

• In vitro:
  
  • Scatchard characterized the dynamics of binding reactions between small molecules and proteins. His theory can be applied to any biological system, where a substance (ligand) binds to a large-molecular binding site (receptor)
• In vivo
  
  • Radio-labeled hormone into the circulation
  • Examine:
    
    • Apperance of the hormone
    • Staying of the hormone
    • Removal of the hormone

Question 6

Dynamics of the ligand-receptor interaction

Analysis

Answer 6

• Scatchard analysis
• Measure the properties of the ligand-receptor interaction
• Two important parameters:
  
  • Bmax
    
    • The total amount of binding sites
  • Kd
    
    • The dissociation constant of the binding site
    • The strength (affinity) of binding formed
• The stronger the ligand-receptor connection is, the more non-labeled hormone is required to displace the radioactive hormone from the receptor

Question 7

Feedback mechanism

Answer 7

• When the central facilitation is inhibited by the increased production of hormones, the hormone production will be inhibited by the concentration of hormones in the system
  
  • Low concentration of hormones will elicit production
  • High concentration of hormones will inhibit production
• Long feedback: from the peripheral gland to the hypothalamus
• Short feedback: from the peripheral gland to the pituitary gland
• Ultra-short feedback: between the hypothalamus and the pituitary gland