Flashcards
Liver
Flashcards do conjunto (14)
- 1What are xenobiotics?Foreign chemical substance not normally found or produced in the body which cannot be used for energy requirements
Can be absorbed across lungs, skin or ingested - 2How are xenobiotics excreted?Bile, urine, sweat and breath
- 3Define: lipophilic?To be able to pass through plasma membranes to reach metabolising enzymes
Non ionised at pH of 7.4
Bound to plasma proteins to be transported in the blood - 4Define: Microsome?A small particle consisting of a piece of endoplasmic reticulum to which ribosomes are attached, so microsomal enzymes are just enzymes found in these microsomes
- 5Describe microsomal enzymes?Mainly Phase I reactions but can do phase II as well
Located on the smooth endoplasmic reticulum
Mostly found in liver hepatocytes but can be found in the liver and the lungs too
Examples include cytochrome P450 , Flacin monooxygenase, UDP glucocoronosyltransferase
Can be actively induced or inhibited by drugs, food, age bacteria and alcohol - 6Describe phase I reactionsAims to may drug more hydrophilic so it can be excreted by kidneys - adds a hydroxyl group
The introduce or expose hydroxyl groups or other reactive sites that can be used for conjugation reactions
Non synthetic catabolic reactions: oxidation, reduction and hydrolysis - 7Describe phase II reactions?Glucuronidation
The addition of glucuronic acid to a substance - 8Describe non microsomal enzymes?Mainly phase II reactions
Located in the cytoplasm and mitochondria of hepatocytes in the liver but also in other tissue too
Non specgfifc
Non inducible, protiein oxidases, esterases, conjugases - 9What is the aim of drug metabolism?To make the drugs more polar so they cannot get across membranes and thus they are more easily excreted
This mostly occurs in the liver - 10How can molecules be oxidised?Hydroxylation (add -OH)
Dealkylation (remove -CH)
Deamination (remove -NH)
Dehydrogination - 11How can a molecule be reduced?Add hydrogen
Saturated unsaturated bonds - 12Describe a hydrolysis reaction?Split amide ( COOH - NH) and ester
- 13Describe functionalisation?Introduces reactive group to a drug
Includes adding or exposing -OH -SH -NH2 -COOH
Product is usually more reactive
Small increase in hydrophilicity
Mainly occur in liver
Catalysed by CP450 - 14Describe cytochrome P450 enzymes?Type of microsomal enzyme
Phase I reactions
Uses haem group to oxidise substances
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- PHASE 1 MED (Gastrointestinal and the Liver ) FlashCards sobre Liver , criado por Erin Dunn em 06-04-2019.
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- Erin Dunn
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