Please use this identifier to cite or link to this item: https://hdl.handle.net/10216/100548
Author(s): Clara Lemos
Ana Faria
Manuela Meireles
Fatima Martel
Rosario Monteiro
Conceicao Calhau
Title: Thiamine is a substrate of organic cation transporters in Caco-2 cells
Issue Date: 2012
Abstract: The aim of this study was to characterize the intestinal absorption of thiamine, by investigating the hypothesis of an involvement of Organic Cation Transporter (OCT) family members in this process. [H-3]-T+ uptake was found to be: 1) time-dependent, 2) Na+- and CI--dependent, 3) pH-dependent, with uptake increasing with a decrease in extracellular pH and decreasing with a decrease in intracellular pH, 4) inhibited by amiloride, 5) inhibited by the thiamine structural analogues oxythiamine and amprolium, 6) inhibited by the unrelated organic cations MPP, clonidine, dopamine, serotonin, 7) inhibited by the OCT inhibitors decynium22 and progesterone. Moreover, the dependence of [H-3]-T+ uptake on phosphorylation/dephosphorylation mechanisms was also investigated and [3H]-T+ uptake was found to be reduced by PKA activation and protein tyrosine phosphatase and alkaline phosphatase inhibition. In conclusion, our results are compatible with the possibility of thiamine being transported not only by ThTrl and/or ThTr2, but also by members of the OCT family of transporters (most probably OCT1 and/or OCT3), thus sharing the same transporters with several other organic cations at the small intestinal level.
Subject: Farmacologia clínica, Medicina básica
Clinical pharmacology, Basic medicine
Scientific areas: Ciências médicas e da saúde::Medicina básica
Medical and Health sciences::Basic medicine
URI: https://repositorio-aberto.up.pt/handle/10216/100548
Document Type: Artigo em Revista Científica Internacional
Rights: restrictedAccess
Appears in Collections:FCUP - Artigo em Revista Científica Internacional
FMUP - Artigo em Revista Científica Internacional

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