Tomomi Uchiyama

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To investigate the involvement of transmembrane segment 7 (TMS7) of hPepT1 in forming the putative central aqueous channel through which the substrate traverses, we individually mutated each of the 21 amino acids in TMS7 to a cysteine and analyzed the mutated transporters using the scanning cysteine accessibility method. Y287C- and M292C-hPepT1 did not(More)
We describe the regulation mechanisms of the Na(+)-dependent neutral amino acid transporter ASCT2 via nitric oxide (NO) in the human intestinal cell line, Caco-2. Exposure of Caco-2 cells to S-nitrosothiol, such as S-nitroso-N-acetyl-DL-penicillamine (SNAP) and S-nitrosoglutathione, and the NO-donor, NOC12, concentration- and time-dependently increased(More)
Purpose. The objective of this study was to provide direct evidence of the relative importance of the His57 residue present in transmembrane domain 2 (TMD 2) and the His121 residue in TMD 4 as proton-binding sites in human PepT1 (hPepT1) by using a novel mutagenesis approach. Methods. His57 and His121 in hPepT1 were each mutated to alanine, arginine, or(More)
Purpose: The objective of this study is to examine the intestinal permeability of novel lipophilic derivatives of DADLE (Tyr- D-Ala-Gly-Phe-D-Leu), an enkephalin analogue, using isolated rat intestinal membranes. Methods: The novel lipophilic derivatives of DADLE were synthesized by chemical modification with various fatty acids at the C terminus. The(More)
Cationic amino acid transport in primary cultured rat pneumocytes exhibiting characteristics of alveolar epithelial type I-like cells are described. Asymmetry and activator ion dependency of (3)H-L-arginine uptake were characterized from the apical or basolateral fluid of pneumocytes grown on permeable support. Substrate specificity of transport was(More)
Resveratrol, a natural polyphenol in grapes, is known to prevent the cardiovascular diseases and to exert the antiangiogenic effect in in vivo models with vascular endothelial growth factor (VEGF) or basic fibroblast growth factor (bFGF). We examined the effect of resveratrol on tubule formation of cultured endothelial F-2 cells. In collagen gel matrix, F-2(More)
We examined the rapid effect of resveratrol on nitric oxide (NO) production in endothelial F-2 cells. During an incubation period of 10 min, resveratrol at low concentrations (<20 microM) had no effect on NO production, whereas it significantly increased NO production at high concentrations (>50 microM). In contrast, pretreatment with resveratrol at low(More)
Studies were conducted in primary cultured rat alveolar epithelial cell monolayers to characterize peptide transporter expression and function. Freshly isolated rat lung alveolar epithelial cells were purified and cultured on permeable support with and without keratinocyte growth factor (KGF). Messenger RNA and protein expression of Pept1 and Pept2 in(More)
Multidrug resistance-associated protein-1 (MRP1) is an integral membrane efflux protein that is implicated in multidrug resistance in cancer, but it is also expressed in normal tissues. The objective of this study was to determine the expression, localization and functional activity of MRP1 in primary cultured rat alveolar epithelial cells of types I- and(More)
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