How does biotransformation occur in liver?
The initial biotransformation of most organic chemicals (phase I metabolism) is catalyzed by the cytochrome P450 enzymes of the endoplasmic reticulum of liver cells. This superfamily of enzymes oxidizes and reduces carbon and a number of heteroatoms.
What is the principle of biotransformation?
In general, biotransformation reactions convert compounds to more polar hydrophilic molecules that are more amenable to excretion, generally via the kidney. Traditionally, biotransformation reactions have been categorized as phase I and phase II reactions.
How is liver metabolized?
The liver is extremely active in oxidizing triglycerides to produce energy. The liver breaks down many more fatty acids that the hepatocytes need, and exports large quantities of acetoacetate into blood where it can be picked up and readily metabolized by other tissues.
What is the name of the liver process in metabolism of drugs?
Phase I metabolism involves functionalization reactions. Phase II drug metabolism is a conjugation reaction. Phase III refers to transporter-mediated elimination of drug and/or metabolites from body normally via liver, gut, kidney, or lung.
What is the main purpose of biotransformation?
The major purpose of biotransformation is to chemically modify (metabolize) poorly excretable lipophilic compounds to more hydrophilic chemicals that are readily excreted in urine and/or bile. Without metabolism, lipophilic xenobiotics accumulate in biota, increasing the potential for toxicity.
What are the two types of biotransformation reactions?
Biotransformation is of two types: Enzymatic and Non-enzymatic. Enzymatic are further divided into Microsomal and Non-microsomal. Enzymatic Elimination is the biotransformation occurring due to various enzymes present in the body.
What is the main goal of biotransformation?
How many phases happen during biotransformation?
It appears that the metabolism of most foreign compounds occurs in two phases.
What is the liver secrete?
The liver secretes bile, a digestive fluid; metabolizes proteins, carbohydrates, and fats; stores glycogen, vitamins, and other substances; synthesizes blood-clotting factors; removes wastes and toxic matter from the blood; regulates blood volume; and destroys old red blood cells.
How does the liver process carbohydrates?
The liver plays a unique role in controlling carbohydrate metabolism by maintaining glucose concentrations in a normal range. This is achieved by a tightly regulated system of enzymes and kinases regulating either glucose breakdown or synthesis in hepatocytes.
How does the liver process drugs?
Most drugs must pass through the liver, which is the primary site for drug metabolism. Once in the liver, enzymes convert prodrugs to active metabolites or convert active drugs to inactive forms. The liver’s primary mechanism for metabolizing drugs is via a specific group of cytochrome P-450 enzymes.
What are the 2 phases in the process of metabolism?
Two phases of metabolism are anabolism and catabolism.
How does biotransformation take place in the liver?
Biotransformation is the metabolic process by which the liver alters or modifies substances entering the body, such as drugs. The process takes place through an interaction of substrates with the cytochrome P450 family of enzymes.
How are hormones transported from the body to the liver?
We ingest them (e.g. medication for diabetes). We absorb them through the skin (e.g. an estrogen patch). Once inside us, they are transported to the liver, where enzymes start the process of breaking them down, known as biotransformation, before putting them to use.
What are some examples of biotransformation of drugs?
For example, bioactive compounds found in grapefruit juice and some other fruit juices, have been found to interrupt metabolism of certain medications by CYP450, causing increased bioavailability (more drug is circulating and, therefore, there is the potential for overdosing).
How does genetics play a role in biotransformation?
Our hereditary uniqueness plays a huge role in biotransformation because there is a genetic variability, called polymorphism, that influences our response to drugs. What this means is that as individuals, we respond differently to substances that we take in.