Liver Detoxification Flashcards
What are xenobiotics?
Foreign substances with no nutritional value and toxic if not excreted in enough time
How are xenobiotic reactions dangerous?
They can react with oxygen to form free radicals which can cause harm and damage cells
What are Phase 1 reactions carried out for?
Functionalization - To form or expose FG’s
What are Phase 2 reactions carried out for?
Conjugation –> Adding a polar substrate to produce hydrophilic metabolites, facilitated by enzymes
What happens in a Conjugation reaction?
Covalent bonds formed, large increase in hydrophilicity
What are cytochrome P450 enzymes used for?
Present in SER, ox sub and reduce O2, to generate free radical
How can drugs interact cytochrome enzyme metabolism?
Induction or Inhibition
How can liver cause drug to be used more effectively? (e.g. opiates)
Can convert active dug into an active metabolite e.g.
Codeine de-methylated to morphine so can be used more effectively
How can liver also be involved in drug conversion?
Convert an inactive/pro drug into an active agent
What are phase 1 reactions?
Primarily redox and hydrolysis to add/expose FGs
What are phase 2 reactions?
Conjugation reactions adding a polar moiety to make compound more water soluble e.g. Glucuronyl or Sulphate
Difference in locations of enzymes in Hepatocytes?
Microsomal: SER
Non-Microsomal: Cytoplasm and Mitochondria
