https://www.gastrojournal.org/article/S0016-5085(01)20970-6/pdf

Organic anion-transporting polypeptide B (OATP-B) and its functional comparison with three other OATPs of human liver

Fluvoxamine is a potent inhibitor of cytochrome P4501A2

Physicians have long been aware of the subtle differences in the responses of patients to medication. The recognition that a part of this variation is inherited, and therefore predictable, created the field of pharmacogenetics fifty years ago. Knowing the gene variants that cause differences among patients has the potential to allow 'personalized' drug therapy and to avoid therapeutic failure and serious side effects.

Pharmacogenetics: five decades of therapeutic lessons from genetic diversity

Most pharmacologically active molecules are lipophilic and remain un-ionized or only partially ionized at physiological pH. Biotransformation means that a lipid-soluble xenobiotic or endobiotic compound is enzymatically transformed into polar, water-soluble, and excretable metabolites. The major organ for drug biotransformation is the liver. The metabolic products often are less active than the parent drug or inactive. However, some biotransformation products (metabolites) may have enhanced activity or toxic effects. Thus biotransformation may include both "detoxication" and "toxication" processes. One of the major enzyme systems that determines the organism's capability of dealing with drugs and chemicals is represented by the cytochrome P450 monooxygenases. Studies in the last 15 years have provided evidence that cytochrome P450 occurs in many different forms or "isozymes" which differ in spectral, chemical, and immunological properties and have different substrate affinities. These isozymes also differ in their regulation and tissue distribution. Recombinant DNA studies indicate that between 40 and 60 structural genes code for different cytochrome P450 isozymes in a single organism. Other enzyme systems include dehydrogenases, oxidases, esterases, reductases, and a number of conjugating enzyme systems including glucuronosyltransferases, sulfotransferases, glutathione S-transferases, etc. Environmental and genetic factors cause interindividual and intraindividual differences in drug metabolism and may alter the balance between toxification and detoxification reactions. Genetic polymorphisms lead to subpopulations of patients with decreased, absent, or even increased activities of certain reactions (e.g., CYP2D6, CYP2C19, N-acetyltransferase polymorphism). Environmental factors such as other drugs, steroids, dietary factors, alcohol, and cigarette smoke can induce or inhibit drug-metabolizing enzymes and cause intraindividual variation.

Overview of enzymes of drug metabolism

High-performance liquid chromatographic assays for bufuralol 1′-hydroxylase, debrisoquine 4-hydroxylase, and dextromethorphan O-demethylase in microsomes and purified cytochrome P-450 isozymes of human liver

https://www.gastrojournal.org/article/0016-5085(83)90026-4/pdf

Bernhard Dick

Papers

Hepatic Monooxygenase Activities in Subjects With a Genetic Defect in Drug Oxidation

Evidence for compromised aldosterone synthase enzyme activity in preeclampsia.