In placenta

Data from a single study in dogs suggest that hepatic first-pass metabolism may limit systemic availability of the parent compound following oral exposure (Braeckman et al. 1983). Placental transfer of methyl parathion was demonstrated in pregnant rats 1-3 days before parturition. Thirty minutes after administration, both methyl parathion and methyl paraoxon were found in fetal brain, liver, and muscle methyl parathion, but not methyl paraoxon, was detected in placenta and maternal liver (Ackermann and Engst 1970). Methyl parathion binds reversibly to serum albumin, but is readily distributed to the tissues (Braeckman et al. 1980, 1983). 

Kekuda, R., et al. Cloning and functional characterization of a potential-sensitive, polyspecific organic cation transporter (OCT3) most abundantly expressed in placenta. J. Biol. Chem. 1998, 273, 15971-15979. 

Burton, PJ. and Waddell, B.J., Dual function of 1 lP-hydroxysteroid dehydrogenase in placenta Modulating placental glucocorticoid passage and local steroid action, Biol. Reprod., 60, 234, 1999. 

Mercuric salts weakly penetrate the placenta barrier however, they can accumulate in placenta [26-29], foetal membranes and amniotic fluid [30], In mice, mercuric chloride (1.5 mg per kg) injected on day 14 of gestation resulted in 0.14% of the injected mercury being transferred to foetal tissues 4 days later [27],... 

Granulocyte CSF was first identified (as CSF-/J) in placenta-conditioned medium and was shown to induce the differentiation of murine myelo-... 

PH domain IPL Pleckstrin PHI (1-105) PSI-BLAST (4) 2 X 10 Human Imprinted in Placenta and Liver... 

Smith SK, He Y, Clark DE, Chamock-Jones DS (2000) Angiogenic growth factor expression in placenta. Semin Perinatol, 24 82-86. 

Strandman T, Koistinen J, Variainen T. 2000. Polybrominated diphenyl ethers (PBDEs) in placenta and human milk. Organohalogen Compounds 47 61-64. 

BCRP (ABCG2) is similar to pGp but has only one ATP-binding domain. It is found in stem cells, where it may function to protect them against toxicants, and also in placenta and the canalicular membrane in hepatocytes. It is upregulated by low oxygen levels. 

A recently discovered human selenoprotein is a thioredoxin reductase which is present in the T cells of the immune system as well as in placenta and other tissues.189 547-549 The 55-kDa protein has one selenocysteine as the penultimate C-terminal residue. Another mammalian selenoprotein, of uncertain function, is the 57-kDa selenoprotein P. It contains over 60% of the... 

Exposure, Intake, and Effects of Toxic and Essential Elements Assessment of steroid hormone disruption in placenta as indicator tissue for monitoring fetal and maternal environment. Biomonitoring of metals is included with evaluation of dietary metal intake (European Commission 2004). 

Schecter et al. (1996b) recently presented data on the levels of CDDs and CDFs in human fetuses (8-14 weeks gestational age with placenta removed) and in placentas from women from the general population who had normal deliveries. On a lipid basis, the total TEQs (CDDs plus CDFs) in a pool of 14 placentas was 10.1 ng/kg half this amount (5. 3 ng/kg) was measured in a pool of 10 fetuses. In an analysis of 43 samples of human milk, Schecter et al. (1996b) found that the total concentration of CDDs and CDFs was 16.7 ng/kg (expressed as TEQ). The authors also calculated that the TEQ body burden for the pooled fetal tissue was 0.034 ng/kg body weight for pooled placentas, they calculated a total TEQ of... 

Schecter A, Startin J, Wright C, et al. 1996e. Concentrations of polychlorinated dibenzo-p-dixions and dibenzofurans in human placental and fetal tissues from the U.S. and in placentas from Yu-Cheng exposed mothers. Chemosphere. 32 551-557. 

The OCT3 was cloned from a human kidney carcinoma cell line (70). The OCT3 mRNA can be detected in multiple tissues including intestine, kidney, and brain with the highest expression noted in placenta (71). This transporter mediates the uptake of neurotransmitters such as epinephrine, norepinephrine, and MPP+ (70). To date, several synonymous variants have been reported for OCT3 (72,73) (www.vanderbilt.edu/kimlab). 

Okey AB, Giannone JV, Smart W, Wong JM, Manchester DK, Parker NB, Feeley MM, Grant DL, Gilman A. Binding of 2,3,7,8-tetrachlorodibenzo-p-dioxin to AH receptor in placentas from normal versus abnormal pregnancy outcomes. Chemosphere 1997 34 1535-1547. 

BCRP is classified in ABCG subfamily other members of this subfamily are involved in sterol transport (269). Unlike P-gp and MRPs, BCRP consists of a single ABC cassette in the amino terminal followed by six putative transmembrane domains however, it forms a homodimer linked by a disulfide bond in the plasma membrane (270,271). Initially, ABCG2 was identified as an mRNA expressed in placenta (272) and as a non-MDRl- and non-MRP-type resistance factor from cell lines selected in the presence of anthracy-clines and mitoxantrone (273). BCRP is expressed widely in the normal tissues (274) and localized on the canalicular membrane of the hepatocytes and apical membranes of epithelial cells (274,275) and brain capillary endothelial cells (276,277). 

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