Catecholamines and Adrenal Disorders

Question 1

Describe Synthesis of Catecholamines

Answer 1

Question 2

Adrenoceptor System: α1 A, B, D

Answer 2

Agonist potency order: Norepinephrine > epinephrine

Selected action of agonist: Smooth muscle contraction

Mechanism: Gq-phospholipase C (PLC) activated, IP3 and calcium up

Question 3

Adrenoceptor System: α2 A, B, C

Answer 3

Agonist potency order: Epinephrine ≥ norepinephrine

Selected action of agonist: Smooth muscle relaxation and neurotransmitter inhibition

Mechanism: Gi: adenylate cyclase inactivated, cAMP down

Question 4

Adrenoceptor System: β₁

Answer 4

Agonist potency order: epinephrine = norepinephrine

Selected action of agonist: Heart muscle contraction

Mechanism: G_s: adenylate cyclase activated, cAMP up

Question 5

Adrenoceptor System: β₂

Answer 5

Agonist potency order: epinephrine >> norepinephrine

Selected action of agonist: Smooth muscle relaxation eg bronchioles, also glycogenolysis

Mechanism: G_s: adenylate cyclase activated, cAMP up (also Gi, see β₂)

Question 6

Adrenoceptor System: β₃

Answer 6

Agonist potency order: norepinephrine > epinephrine

Selected action of agonist: Enhance lipolysis

Mechanism: G_s: adenylate cyclase activated, cAMP up

Question 7

Pathology

Answer 7

Question 8

Cushing’s Disease

Answer 8

Question 9

Describe Addison’s Disease

Answer 9

• Disease in which patients lack cortisol from zona fasiculata, and thus lacks negative feedback that suppresses ACTH production
• Result: overproduction of ACTH
• Skin color will darken
• JFK had Addison’s disease and was treated with cortisol injections