Metabolism of Poisons

Question 1

purpose of metabolism

Answer 1

facilitate excretion of toxins

transform compounds into less toxic forms

stores compounds to prevent toxicity

Question 2

What are the consequences of Biotransformation?

Answer 2

Increased Elimination

Changes in Toxicity

Increased metabolite size

Question 3

Meaning of ‘increased elimination’

Answer 3

metabolites are more polar and water-soluble than the parent compound

Shortens plasma half-life

Question 4

Types of Biotransformation

Answer 4

Phase I

Phase II

Question 5

Phase I biotransformation

Answer 5

Adds a functional group

(Oxidation, reduction, hydrolysis)

Question 6

Phase II Biotransformation

Answer 6

Conjugation reactions to increase water solubility (e.g. glucuronidation, sulphation, glutathione conjugation)

Question 7

Phase I Biotransformation reactions

Answer 7

Oxidation, involving cytochrome P-450 enzymes.

Reduction, hydrolysis and hydration also occur

Question 8

Phase II Biotransformation reactions

Answer 8

Addition of polar groups ( e.g. glutathione conjugation, sulphation, acetylation)

Results in less toxic, more excretable compounds