Cathecholamine Metabolism

Question 1

What is the end product of norepinephrine metabolism?

Answer 1

Oh boy!

Question 2

What are the 2 metabolic pathways for norepinephrine and epinephrine?

Answer 2

1. Monoamine oxidase (MAO)
2. Catechol-O-methyltransferase (COMT)

Question 3

The —– and the —– are the principal sites of metabolism of catecholamines that have entered the circulation

(this includes I V administration)

Answer 3

kidneys and liver

Question 4

Only —–% of norepinephrine is excreted unchanged in the urine

Answer 4

~ 5%

Question 5

The final byproduct of norepinephrine and epinephrine metabolism is —–.

Answer 5

Vanillyl-Mandelic Acid (VMA).

Question 6

The final byproduct of norepinephrine and epinephrine metabolism is vanillylmandelic acid (VMA). Another name for this compound is —–.

Answer 6

3- methoxy-4-hydroxymandelic acid

Question 7

—– measurement of VMA permits a general assessment of overall SNS activity

Answer 7

Urine measurement

Question 8

The vast majority of VMA in the urine is the result of —– of norepinephrine

Answer 8

De-amination of norepinephrine

Question 9

The vast majority of VMA in the urine is the result of de-amination of norepinephrine in —– nerve endings

Answer 9

Adrenergic post-ganglionic nerve endings

Question 10

An elevated level of VMA in the urine aids in the diagnosis of —–.

Answer 10

Pheochromocytoma

Question 11

What is the end product of norepinephrine metabolism?

Answer 11

Vanillylmandelic acid

Question 12

Name 2 are Intermediate Metabolites of norepinephrine

Answer 12

metanephrine and normetanephrine

Question 13

Name the precursor of NE synthesis.

Answer 13

Tyrosine

Question 14

References:

Answer 14

• Barash. Clinical Anesthesia. 8th ed**.* 2017.* *p. 341-342.
• Flood* . Stoelting’s Pharmacalogy & Physiology in Anesthetic Practice . 5th ed. 2015. p**. 83 .