Xenobiotic distribution

Xenobiotics distribution, extra and intracellular accumulation and storage... 

A PBPK model comprises a series of anatomically well-defined compartments that represent organs or tissues in which a xenobiotic distributes or exerts its toxic effects (Figure 4). These anatomical compartments are interconnected by the blood circulation (i.e., arterial blood to and venous blood from the tissues). The physiological and anatomical determinants for different species, including humans (e.g., alveolar ventilation rate, blood flow rates, and tissue volumes), are usually abundantly documented in the literature. Physicochemical parameters - namely partition coefficients that describe the relative solubility... 

Xenobiotics enter in the bloodstream, following one of the described absorption routes, are distributed into the body and undertaken by different organs. It is possible that a part of the xenobiotics distributed into the body may be stored in tissues or even in the blood. A word commonly used to refer to storage of a pollutant at higher levels than those found in the environment is bioaccumulation, for example, PAHs, PCBs, dioxins and some organometallic forms of metals bioaccumulate in fat, fluoride and lead in bones etc. Sometimes biomagnification takes place, as a bioaccumulation process within the trophic chain, in indirect relationship with biota. 

An important factor in determining the course of uptake, transport, and distribution of xenobiotics is their polarity. Compounds of low polarity tend to be lipophilic and of low water solubility. Compounds of high polarity tend to be hydrophilic and of low fat solubility. The balance between the lipophilicity and hydrophilicity of any compound is indicated by its octanol-water partition coefficient (K J, a value determined when equilibrium is reached between the two adjoining phases ... 

P-glycoprotein, a plasma membrane transport protein, is present in the gut, brain, liver, and kidneys 42 This protein provides a biologic barrier by eliminating toxic substances and xenobiotics that may accumulate in these organs. P-glycoprotein plays an important role in the absorption and distribution of many medications. Medications that are CYP3A4 substrates, inhibitors, or inducers are also often affected by P-glycoprotein therefore, the potential for even more DDIs exists in transplant recipients.42... 

Smejtek, P. Wang, S., Distribution of hydrophobic ionizable xenobiotics between water and lipid membrane Pentachlorophenol and pentachlorophenate. A comparison with octanol-water partition, Arch. Environ. Contam. Toxicol. 25, 394 404 (1993). 

Bioavailability of Metals, Nonmetals and Xenobiotics Immobilized on Soil Components, (4) Distribution and Activity of Biomolecules in Terrestrial Systems, (5) Interactions between Soil Microbial Biomass and Organic Matter/Nutrient Transformations, and (6) Impact of Interactions among Soil Mineral Colloids, Organic Matter and Biota on Risk Assessment and Restoration of Terrestrial Ecosystems. There were 2 plenary lectures, 9 invited speakers, 36 oral presentations and 45 posters. Dr. N. Senesi from University of Bari, Italy, presented an IUPAC lecture entitled Metal-Humic... 

Nojiri H, Shintani M, Omori T (2004) Divergence of mobile genetic elements involved in the distribution of xenobiotic-catabolic capacity. Appl Microbiol Biotechnol 64 154-174... 

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