Glukuronidiin

Glukuronidiin, or glucuronide, refers to a class of chemical conjugates formed when glucuronic acid is attached to another molecule. This process, glucuronidation, is a major phase II metabolic pathway in which UDP-glucuronosyltransferase (UGT) enzymes transfer glucuronic acid from UDP-glucuronic acid to substrates such as drugs, bilirubin, hormones, and xenobiotics. The resulting glucuronides are typically more water-soluble and are prepared for elimination from the body.

Glukuronidiin can be formed at different functional sites. O-glucuronidation attaches glucuronic acid to hydroxyl groups, N-glucuronidation to amine groups, and acyl glucuronidation to carboxyl groups, the latter producing acyl glucuronides. The linkage is generally through an ester or glycosidic bond to the donor sugar, with the liver housing the majority of the responsible UGT enzymes, though glucuronidation also occurs in the intestine, kidney, and other tissues.

Physiological role of glukuronidiin centers on detoxification and excretion. By increasing hydrophilicity, glucuronides are more readily excreted via urine or bile. In the liver, glucuronides may be secreted into bile and enter the enterohepatic circulation; intestinal bacteria can sometimes hydrolyze glucuronides, releasing active aglycones back into circulation.

Examples have clinical and pharmacological relevance. Bilirubin is conjugated to form bilirubin diglucuronide for biliary excretion. Many drugs, including acetaminophen and morphine, are eliminated as glucuronides. Genetic variations in UGT enzymes and drug-drug interactions can alter glucuronidation rates, influencing drug clearance and toxicity risk.

Research on glukuronidiin aids understanding of pharmacokinetics, toxicology, and hepatic function, as well as the metabolism of endogenous substances.