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 hepatic enzyme induction?
Hepatic enzyme induction is generally an adaptive response associated with increases in liver weight, induction of gene expression, and morphological changes in hepatocytes.
Which does not induce microsomal enzymes Mcq?
3.16 The drug which DOES NOT induce microsomal enzymes is: Cimetidine.
What does enzyme induction do?
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 microsomal enzyme induction?
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.
What is microsomal enzyme in pharmacology?
Inducers of microsomal enzymes stimulate the metabolism or synthesis of several normal body substrates such as steroid hormones, pyridine nucleotides, cytochromes, and bilirubin. Evidence has accumulated that steroids are normal body substrates of drug-metabolizing enzymes in liver microsomes.
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.
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 hepatic enzyme activity?
Hepatic enzyme activity is the major factor determining elimination rate of high-clearance drugs in cirrhosis. Hepatology.
What is hepatic microsomal enzyme?
Drugs are metabolized in the liver using several enzyme-catalyzed processes. These enzymes are collectively referred to as the hepatic microsomal enzyme system, and they are usually present in the endoplasmic reticulum of hepatocytes.
What is microsomal induction?
What are hepatic microsomal enzymes?
By Dr. Drugs are metabolized in the liver using several enzyme-catalyzed processes. These enzymes are collectively referred to as the hepatic microsomal enzyme system, and they are usually present in the endoplasmic reticulum of hepatocytes.
How is the hepatic microsomal enzyme system activated?
The microsomal enzyme system can be activated by using an inducer drug that can bind to the receptor present in the cytoplasm or nucleus. This receptor-inducer complex then travels to the nucleus and forms a dimer. This heterodimer may bind to promoter regions of P450 genes, and increase gene expression.
Which is a drug that induces microsomal enzyme?
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 does microsomal enzyme induction and atherosclerosis take place?
Microsomal enzyme induction, lipoproteins and atherosclerosis The liver is the principal site for the synthesis and elimination of lipoproteins circulating in plasma, and alterations in hepatic function influence plasma lipoprotein levels.
How long does induction of the enzyme system last?
The induction of the enzyme system can increase the metabolic rate by two to four folds. This increase in the rate of enzyme production is maintained for as long as the inducer drug is present, and may return to its original values over a period of one to three weeks. What happens to drugs once they have been metabolized?