Xenobiotics Flashcards
How many isoforms of cytochrome P450 are present in the endoplasmic reticulum of the human liver?
Six isoforms of cytochrome P450 are present in the endoplasmic reticulum of the human liver.
What is the enzyme responsible for using NADPH to yield the reduced cytochrome P450?
NADPH-cytochrome P450 reductase is the enzyme responsible for using NADPH to yield the reduced cytochrome P450.
Which lipid is the preferred component of the cytochrome P450 system?
Phosphatidylcholine is the preferred lipid component of the cytochrome P450 system.
What is the main organ involved in the metabolism of xenobiotics in the human body?
The liver is the main organ involved in the metabolism of xenobiotics in the human body.
What are the principal classes of xenobiotics of medical relevance?
The principal classes of xenobiotics of medical relevance are drugs, chemical carcinogens, and environmental compounds.
What is the major reaction involved in phase 1 of xenobiotic metabolism?
Hydroxylation is the major reaction involved in phase 1 of xenobiotic metabolism.
What type of enzymes catalyze hydroxylation reactions in phase 1 of xenobiotic metabolism?
Cytochrome P450 enzymes catalyze hydroxylation reactions in phase 1 of xenobiotic metabolism.
What are some reactions catalyzed by cytochrome P450 enzymes besides hydroxylation?
Besides hydroxylation, cytochrome P450 enzymes catalyze reactions involving deamination, dehalogenation, desulfuration, epoxidation, peroxygenation, and reduction.
In phase 2 of xenobiotic metabolism, what are the compounds produced in phase 1 converted into?
In phase 2 of xenobiotic metabolism, compounds produced in phase 1 are converted into polar metabolites.
What are some examples of polar metabolites produced in phase 2 of xenobiotic metabolism?
Polar metabolites in phase 2 of xenobiotic metabolism include conjugates with glucuronic acid, sulfate, glutathione, acetate, or certain amino acids.
What is the mechanism of induction of cytochrome P450 in the smooth endoplasmic reticulum?
The induction of cytochrome P450 in the smooth endoplasmic reticulum is mediated by the administration of drugs like phenobarbital.
What are the clinical implications of the induction of cytochrome P450?
The induction of cytochrome P450 has clinical implications, particularly in drug interactions and metabolism.
What is pharmacogenomics and how does it relate to drug design?
Pharmacogenomics integrates genomics, proteomics, and other disciplines to design drugs based on genetic profiles and polymorphisms.
How many manufactured environmental chemicals exist, and what happens to most of them in the human body?
More than 200,000 manufactured environmental chemicals exist, with most undergoing metabolism in the human body.
What is the role of the liver in the metabolism of xenobiotics?
The liver plays a key role in metabolizing xenobiotics due to its high concentration of enzymes involved in xenobiotic metabolism.
What are some examples of xenobiotics that humans are commonly exposed to?
Humans are commonly exposed to xenobiotics such as drugs, chemical carcinogens, environmental pollutants like PCBs, and insecticides.
What are the major effects of xenobiotics in terms of toxicity?
Xenobiotics can have major effects in terms of toxicity, necessitating proper metabolism and elimination from the body.
How does the administration of phenobarbital affect cytochrome P450 levels in the liver?
The administration of phenobarbital can increase cytochrome P450 levels in the liver, leading to enzyme induction.
What is the role of NADPH-cytochrome P450 reductase in the reaction mechanism of cytochrome P450?
NADPH-cytochrome P450 reductase is involved in the reduction of cytochrome P450 using NADPH in the reaction mechanism.
What is the function of cytochrome b5 in the cytochrome P450 system?
Cytochrome b5 may act as an electron donor in some cases in the cytochrome P450 system.
What are some compounds that have found their way into the environment and are considered xenobiotics?
Compounds like polychlorinated biphenyls (PCBs) and certain insecticides are examples of xenobiotics found in the environment.
How many enzymes catalyze reactions involved in xenobiotic metabolism?
At least 30 different enzymes catalyze reactions involved in xenobiotic metabolism.
What are the different conjugation reactions involved in phase 2 of xenobiotic metabolism?
Conjugation reactions in phase 2 of xenobiotic metabolism include glucuronidation, sulfation, glutathione conjugation, acetylation, and methylation.
How does the liver respond to the administration of phenobarbital in terms of cytochrome P450 levels?
The administration of phenobarbital can cause hypertrophy of the liver due to increased cytochrome P450 levels.
