Glucuronidation takes place in ?
Ans. is 'a' i.e., Liver GLUCURONIDATION This is the most impoant synthetic reaction carried out by a group of UDP-glucuronosyl transferases (UGTs). Glucuronidation occurs mainly in the liver, although the enzyme responsible for its catalysis, UDP?glucuronyltransferase, has been found in all major body organs (e.g., intestine, kidneys, brain, adrenal gland, spleen, and thymus). Compounds with a hydroxyl or carboxylic acid group are easily conjugated with glucuronic acid which is derived from glucose. Examples are- chloramphenicol, aspirin, paracetamol, lorazepam, morphine, metronidazole. Not only drugs but endogenous substrates like bilirubin, steroidal hormones and thyroxine utilize this pathway. Glucuronidation increases the molecular weight of the drug which ours its excretion in bile. Drug glucuronides excreted in bile can be hydrolysed bybacteria in the gut-the liberated drug is reabsorbed and undergoes the same fate. This enterohepatic cycling of the drug prolongs its action, e.g. phenolphthalein, oral contraceptives.
Liver
RBC
Pancreas
Thyroid