Question

44.Detoxifying role of liver. Role of oxidases and transferases.

(please more explanation Im medicine student) thank you..

Answer 1

The liver plays an important rôle in protecting the organism from potentially toxic chemical insults through its capacity to convert lipophiles into more water-soluble metabolites which can be efficiently eliminated from the body via the urine. This protective ability of the liver stems from the expression of a wide variety of xenobiotic biotransforming enzymes whose common underlying feature is their ability to catalyse the oxidation, reduction and hydrolysis (Phase I) and/or conjugation (Phase II) of functional groups on drug and chemical molecules.

The broad substrate specificity, isoenzyme multiplicity and inducibility of many of these enzyme systems make them particularly well adapted to handling the vast array of different chemical structures in the environment to which we are exposed daily. However, some chemicals may also be converted to more toxic metabolites by certain of these enzymes, implying that variations in the latter may be important predisposing factors for toxicity.

Pharmacogenetic defects of xenobiotic biotransformation enzymes, a subclass of inborn errors of metabolism which are manifested only upon drug challenge, introduce marked variation into human populations for the pharmacokinetics and pharmacodynamics of therapeutic and toxic agents, and thus may have important clinical consequences for drug efficacy and toxicity.

From drugs and alcohol to unknown foreign substances, the liver filter and detoxify the materials not meant to be in our body. Ensuring toxins are safely removed from your blood is one of the liver’s most critical jobs.   

• The first step uses enzymes and oxygen to burn toxins, especially fatty ones.
• The second detox step combines toxins with amino acids so they can be removed from the liver through bile or urine.
• Specific external toxins: certain medications, food additives, preservatives, food colorings, sweeteners, flavor enhancers, chemicals used in agriculture, alcohols, volatile organic compounds, fumes, air pollution and many other factors.