• The metabolism of xenobiotics is often divided into three phases: modification, conjugation and excretion. (bionity.com)
  • The toxicokinetic profile of the test substance was not determined by actual absorption, distribution, metabolism or excretion measurements. (europa.eu)
  • Significant contributions of other mechanisms such as inhibition of mdr1-mediated drug efflux during gastrointestinal absorption, inhibition of bosentan metabolism, or inhibition of hepatobiliary excretion seemed to be unlikely. (aspetjournals.org)
  • Several reviews and reports present the advantages and limitations of the currently available algorithms and software for in silico modelling of the drug dissolution/bioavailability, oral absorption rate/fraction, volume of distribution, path- ways, affinities or rates of metabolism, renal excretion rate as well as affinity for specific transporters [3-20]. (cdc.gov)
  • The substance does not indicate a significant potential for accumulation, when taking into account the predicted behaviour concerning absorption and metabolism. (europa.eu)
  • Cholecalciferol (D3) is converted to active forms by hydroxylation, which then play crucial roles on the absorption, metabolism, and cellular use of calcium. (diagnose-me.com)
  • Метаболізм і виведення Pharmacokinetics refers to the processes of drug absorption, distribution, metabolism, and elimination. (msdmanuals.com)
  • Довідкові матеріали щодо абсорбції Pharmacokinetics refers to the processes of drug absorption, distribution, metabolism, and elimination. (msdmanuals.com)
  • Alterations in intestinal flora that aid metabolism may also affect absorption in the gut. (msdmanuals.com)
  • The pharmaceutical literature consists of numerous examples of 2-D QSARs, 3-D QSARs and expert systems for modelling the individual components or phases of drug disposition and pharmacokinetics (i.e. absorption, distribution, metabolism and *Corresponding author. (cdc.gov)
  • SKF 525-A was a more potent inhibitor of allylic hydroxylation than was metyrapone, but both inhibitors caused greater inhibition of epoxidation than of hydroxylation. (cdc.gov)
  • Inhibition experiments were performed using (S)-[2H4]propafenone as an inhibitor of the 5-hydroxylation of (R)-propafenone, and vice versa. (aspetjournals.org)
  • Application of the model revealed Ki values of 2.9 and 5.2 microM for the inhibition of 5-hydroxylation of (S)-[2H4]-propafenone by (R)-propafenone and for inhibition of 5-hydroxylation of (R)-propafenone by (S)-[2H4]-propafenone, respectively. (aspetjournals.org)
  • Because beta-blocking properties of propafenone reside in the S-enantiomer, inhibition of metabolism of this enantiomer by (R)-propafenone may have therapeutic consequences. (aspetjournals.org)
  • It also demonstrates that inhibition of uptake into the liver might become rate-limiting in the overall elimination process even for compounds whose clearance is dependent on metabolism. (aspetjournals.org)
  • It is, however, clear that inhibition of CYP3A4-mediated metabolism by cyclosporin A alone is insufficient to explain the increased bosentan concentrations and that inhibition of hepatocellular uptake offers an attractive mechanistic alternative also in human. (aspetjournals.org)
  • The prolyl hydroxylation of hypoxia-inducible factor 1α (HIF-1α) mediated by the EGLN-pVHL pathway represents a classic signalling mechanism that mediates cellular adaptation under hypoxia. (nature.com)
  • Prolonged hypoxia promotes the activation of RIPK1 kinase by modulating its proline hydroxylation, independent of the TNFα-TNFR1 pathway. (nature.com)
  • Our findings illustrate a key role of the EGLN-pVHL pathway in suppressing RIPK1 activation under normoxic conditions to promote cell survival and a model by which hypoxia promotes RIPK1 activation through modulating its proline hydroxylation to mediate cell death and inflammation in human diseases, independent of TNFR1. (nature.com)
  • These conditions may result in failure of osteoid calcification (rickets) in children because of a disruption in the pathway of either vitamin D or phosphate metabolism. (medscape.com)
  • Conversion of cholesterol to 24S-OHC is mediated by cholesterol 24S-hydroxylase in the brain, which is the major pathway for oxysterol elimination, followed by oxidation through hepatic first-pass metabolism by CYP39A1. (mdpi.com)
  • The classic pathway involves the hydroxylation of cholesterol, while the alternate pathway utilizes oxysterols as precursors. (randox.com)
  • We used the cytochrome P450IID6-mediated 5-hydroxylation of propafenone as a model pathway, because this metabolic step constitutes the major route of biotransformation of propafenone. (aspetjournals.org)
  • Cytochrome P450-dependent alpha-hydroxylation, followed by sulfonation, represents a metabolic activation pathway, producing products capable of covalent DNA adduction. (oregonstate.edu)
  • However, the intoduction of the fluorine atom at the terminal carbon atom of the double bond favors the ring hydroxylation over a side-chain metabolic oxidation pathway, by which coniferyl alcohol is produced. (usda.gov)
  • Moreover, the use of such correlation analyses for determining the metabolic specificity of CYP2C19 and/or CYP2C9 toward tolbutamide suffers from inherent limitations, including the inability to reveal strong relationships when allelic variants exist at a relatively high frequency, but contribute only slightly to tolbutamide hydroxylation. (aspetjournals.org)
  • CEE significantly decreased CYP1A2 (caffeine metabolic ratio: 0.57 +/- 0.20 before, 0.40 +/- 0.20 after, P = .001) and significantly increased CYP2D6 (dextromethorphan/dextrorphan ratio: 0.0116 +/- 0.0143 before, 0.0084 +/- 0.0135 after, P = .022) metabolism. (nih.gov)
  • The course extends the knowledge of biochemistry acquired in the course Biochemistry I and deals with integration of biochemical processes in human body.Upon completion of this course the student should understand: biochemical processes characteristic for individual organs and tissues and principles of their regulation, metabolic interrelationships between metabolism of nutrients under various conditions in organism, principles of maintenance of homeostasis and acid-base equilibrium in the body. (muni.cz)
  • Metabolic fate of chylomicrons and VLDL, the metabolism of HDL. (muni.cz)
  • Xenobiotic metabolism is the set of metabolic pathways that chemically modify xenobiotics , which are compounds foreign to an organism's normal biochemistry, such as drugs and poisons. (bionity.com)
  • These reactions often act to detoxify poisonous compounds, although in some cases the intermediates in xenobiotic metabolism can themselves be the cause of toxic effects. (bionity.com)
  • Xenobiotic metabolism is commonly divided into three phases. (bionity.com)
  • The actions of some drugs as substrates or inhibitors of enzymes involved in xenobiotic metabolism are a common reason for hazardous drug interactions . (bionity.com)
  • These pathways are also important in environmental science, with the xenobiotic metabolism of microorganisms determining whether a pollutant will be broken down during bioremediation , or persist in the environment. (bionity.com)
  • Vitamin E, nuclear receptors and xenobiotic metabolism. (oregonstate.edu)
  • Although most studies have implicated CYP2C9 as the exclusive catalyst of hepatic tolbutamide hydroxylation in humans, there is evidence that other CYP2C enzymes (e.g. (aspetjournals.org)
  • 15%) inhibitory effect on S -mephenytoin 4′-hydroxylation by purified CYP2C19 or hepatic microsomes containing CYP2C19. (aspetjournals.org)
  • Assessing the contribution of CYP2C19 to hepatic tolbutamide hydroxylation has been challenging for several reasons. (aspetjournals.org)
  • FXR also modulates lipid transport and metabolism, as well as hepatic gluconeogenesis. (randox.com)
  • The use of smokeless tobacco by in the mouth, against the cheek or humans is a voluntary practice en behind the lip and sucked (dipped) Evaluations of smokeless tobac gaged in by hundreds of mil ions of or chewed. (who.int)
  • The first hydroxylation occurs at position 25 in the liver, producing calcidiol (25-hydroxycholecalciferol), which circulates in the plasma as the most abundant of the vitamin D metabolites and is thought to be a good indicator of overall vitamin D status. (medscape.com)
  • Parathyroid hormone facilitates the 1-hydroxylation step in vitamin D metabolism. (medscape.com)
  • In this review, we summarize current knowledge about vitamin D metabolism in general, its role in diabetes mellitus (mainly type 2) and diabetic complications (mainly diabetic kidney disease), and potential therapeutic perspectives including vitamin D signalling as a druggable target. (karger.com)
  • Magnesium plays a key role in this activation through use as a co-factor in the vitamin D binding proteins as well as being required in the process of hydroxylation. (bodybuilding.com)
  • If there's no vitamin C around, there's no hydroxylation. (bodybuilding.com)
  • Lower plasma alpha-carboxyethyl-hydroxychroman after deuterium-labeled alpha-tocopherol supplementation suggests decreased vitamin E metabolism in smokers. (oregonstate.edu)
  • When taking doses of vitamin D3 in excess of 1100 IU per day, regular blood chemistry tests should be taken to monitor kidney function and serum calcium metabolism. (diagnose-me.com)
  • Vitamin D is a lipophilic hormone playing a key role in bone metabolism and calcium homeostasis, [ 1 ] and it is also involved in many other pathological processes [ 2 ] commonly linked with obesity. (medscape.com)
  • To achieve its biological function, 1,25-dihydroxyvitamin D3 requires two sequential hydroxylation steps from vitamin D3 catalyzed by 25-hydroxylase and 1 α -hydroxylase. (medscape.com)
  • The calcium sulfonate target substance is expected to be extensively metabolised (metabolism by cytochrome P450 enzymes, followed by omega- and beta-oxidation and cleavage of the aromatic ring and desulfonation) and to be eliminated mainly via the urine and also via the bile. (europa.eu)
  • In conclusion, the enantiomers of propafenone interact with respect to 5-hydroxylation, with (R)-propafenone being a more potent inhibitor than the S-enantiomer with respect to cytochrome P450IID6-mediated 5-hydroxylation. (aspetjournals.org)
  • Acetaminophen Normal Metabolism? (flashcardmachine.com)
  • [1] The major challenge faced by xenobiotic detoxification systems is that they must therefore be able to remove the almost limitless number of possible xenobiotic compounds from the complex mixture of chemicals involved in normal metabolism . (bionity.com)
  • The detoxification of the reactive by-products of normal metabolism cannot achieved by the systems outlined above. (bionity.com)
  • Monospecific anti-CYP2C9 was also found to inhibit rates of tolbutamide hydroxylation by 93 ± 4 and 78 ± 6% in CYP2C19-deficient and CYP2C19-containing human liver microsomes, respectively. (aspetjournals.org)
  • Taken together, our results indicate that both CYP2C9 and CYP2C19 are involved in tolbutamide hydroxylation by human liver microsomes, and that CYP2C19 underlies at least 14 to 22% of tolbutamide metabolism. (aspetjournals.org)
  • CEE had no overall effect on CYP2C19, CYP2E1, CYP-mediated dapsone metabolism, and N-acetyltransferase 2. (nih.gov)
  • CEE significantly influenced CYP1A2, CYP2D6, and CYP-mediated dapsone oxidative metabolism but not CYP2C19, CYP2E1, or N-acetyltransferase 2 metabolism in postmenopausal women. (nih.gov)
  • Enantiomer/enantiomer interaction of (S)- and (R)-propafenone for cytochrome P450IID6-catalyzed 5-hydroxylation: in vitro evaluation of the mechanism. (aspetjournals.org)
  • Tolbutamide is a sulfonylurea-type oral hypoglycemic agent whose action is terminated by hydroxylation of the tolylsulfonyl methyl moiety catalyzed by cytochrome P-450 (CYP) enzymes of the human CYP2C subfamily. (aspetjournals.org)
  • Stereoselective disposition of the enantiomers can arise from metabolism of the enantiomers via different routes catalyzed by different enzymes. (aspetjournals.org)
  • Cholesterol metabolism in the brain is independent of peripheral tissues due to the blood-brain barrier (BBB) that impairs the entrance of the protein-bound lipid into the central nervous system (CNS). (frontiersin.org)
  • Hydroxylation, in this case, is the act of replacing lone hydrogens on the exposed proline and lysine amino acids with hydroxyl groups (an oxygen and hydrogen bonded). (bodybuilding.com)
  • These proteins participate in all major pathways of electron transport: photosynthesis, respiration, hydroxylation and bacterial hydrogen and nitrogen fixation. (bvsalud.org)
  • Here, we briefly describe carotenoid biosynthesis and highlight the latest advances and discoveries related to synthetic carotenoid metabolism in plants and microorganisms. (frontiersin.org)
  • For example, inherent differences in nitrogen metabolism of plant- and insect-associated microbiomes may dictate whether neonicotinoid-based insecticides ultimately exert antimicrobial activities or not. (researchgate.net)
  • The reactions in these pathways are of particular interest in medicine as part of drug metabolism and as a factor contributing to multidrug resistance in infectious diseases and cancer chemotherapy . (bionity.com)
  • Some of the estrogenic contaminants of technical grade methoxychlor are the same as those formed by metabolism in vivo (Bulger et al. (cdc.gov)
  • The integration of intermediary metabolism at the tissue and organ level. (muni.cz)
  • The effects of aging impact all organ systems by affecting physiologic responsiveness, metabolism, and body composition, among other changes. (psychiatrist.com)
  • A novel monooxygenase gene, dipD, was crucial for the initial hydroxylation of DPA into 3HDPA and proposed to encode the key catalytic component of the multicomponent DPA monooxygenase. (bvsalud.org)
  • One key receptor associated with bile acid metabolism is the Farnesoid X receptor (FXR). (randox.com)
  • The genes responsible for the initial hydroxylation of DPA to 3-hydroxyl-dipicolinic acid were investigated in Alcaligenes faecalis strain JQ135. (bvsalud.org)
  • The role of flavin-containing monooxygenase (FMO) in the metabolism of tamoxifen and other tertiary amines. (oregonstate.edu)
  • Prolyl hydroxylation of RIPK1 mediated by EGLN1 promotes the binding of RIPK1 with pVHL to suppress its activation under normoxic conditions. (nature.com)
  • As such, inhibiting proline hydroxylation of RIPK1 promotes RIPK1 activation to trigger cell death and inflammation. (nature.com)
  • One of the most common modifications is hydroxylation catalysed by the cytochrome P-450-dependent mixed-function oxidase system . (bionity.com)
  • Its application to a number of PAH cohorts from international collaborators generated evidence of elevated 16-hydroxylation in disease. (gla.ac.uk)