What is meant by enzyme induction?

Enzyme induction refers to an increase in the rate of hepatic metabolism, mediated by increased transcription of mRNA encoding the genes for drug-metabolizing enzymes. This leads to a decrease in the concentrations of drugs metabolized by the same enzyme.

What is a microsomal enzyme?

A collection of enzymes in the smooth endoplasmic reticulum of liver cells that modify molecules to make them more POLAR and less lipid-soluble.

What is the significance of hepatic microsomal enzyme induction?

Hepatic microsomal enzymes play an important role in thyroid hormone homeostasis. Glucuronidation of thyroxine is the rate limiting step in the biliary excretion of thyroxine in the rat; the monodeiodinases are important in the conversion of T4 to T3 and reverse T3 and subsequent deiodinations.

What is the difference between microsomal and non microsomal enzymes?

Non-microsomal enzymes: Enzymes occurring in organelles/sites other than endoplasmic reticulum (microsomes) are called non-microsomal enzymes. These are usually present in the cytoplasm, mitochondria, etc. and occur mainly in the liver, Gl tract, plasma and other tissues.

What is microsomal enzyme inhibitor?

The microsomal enzymes that metabolize drugs are localized in the smooth endoplasmic reticulum. Several drugs, including fluconazole, spironolactone, and metronidazole, can inhibit cytochrome P450 enzyme activity. This inhibition reduces the metabolism of potential substrates and secondarily delays their elimination.

Where is microsomal enzymes located?

the endoplasmic reticulum
Microsomal enzymes are typically found in the endoplasmic reticulum of hepatocytes. Microsomes are fragments of endoplasmic reticulum and attached ribosomes that are isolated together when homogenized cells are centrifuged.

What is the meaning of microsomal?

Definition of microsome 1 : any of various minute cellular structures. 2 : a particle in a particulate fraction that is obtained by heavy centrifugation of broken cells and consists of various amounts of ribosomes, fragmented endoplasmic reticulum, and mitochondrial cristae.

What is the microsomal membrane?

Microsomes form when tissues or cells are broken by homogenization. During cellular disruption, membranes such as the plasma membrane (PM), endoplasmic reticulum (ER), tonoplast, Golgi apparatus, and endomembranes break into smaller fragments that then reseal into small enclosed vesicles referred to as microsomes.

Which drug induces microsomal enzymes?

Microsomal enzyme inducing drugs such as phenytoin, phenobarbital and carbamazepine, and also alcohol, influence serum lipid and apoprotein concentrations. The inducers increase the concentrations of hepatic microsomal enzyme and apo A-I mRNA, and also proteins and phospholipids.

Where are microsomal enzymes present?

Microsomal enzymes are typically found in the endoplasmic reticulum of hepatocytes.

What is microsomal oxidation?

The microsomal ethanol oxidizing system (MEOS) is an alternate pathway of ethanol metabolism that occurs in the smooth endoplasmic reticulum in the oxidation of ethanol to acetaldehyde. The MEOS pathway requires the CYP2E1 enzyme, part of the cytochrome P450 family of enzymes, to convert ethanol to acetaldehyde.

What is microsomal reaction?

Microsomal enzymes catalysed majority of drug biotransformation reaction. The large variety of microsomal enzyme catalyse oxidative, reductive & hydrolytic and glucouronidation reactions. They are located on smooth endoplasmic reticulum, mainly in liver then kidney, lungs, intestinal mucosa.