Non-Involvement of the Human Monocarboxylic Acid Transporter 1 (MCT1) in the Transport of Phenolic Acid
Phenolic acids such as <I>p</I>-coumaric acid and microbial metabolites of poorly absorbed polyphenols are absorbed by the monocarboxylic acid transporter (MCT)-mediated transport system which is identical to the fluorescein/H<SUP>+</SUP> cotransport system. We focus here on the physiological impact of MCT-mediated absorption and distribution. We examined whether MCT1, the best-characterized isoform found in almost all tissues, is involved in this MCT-mediated transport system. The induction of MCT1 expression in Caco-2 cells by a treatment with sodium butyrate (NaBut) did not increase the fluorescein permeability. Moreover, the transfection of Caco-2 cells with an expression vector encoding MCT1 caused no increase in either the permeability or uptake of fluorescein. Furthermore, in the MCT1-expressing oocytes, no increase of <I>p</I>-coumaric acid uptake was apparent, whereas the uptake of salicylic acid, a substrate of MCT1, nearly doubled. Our data therefore establish that MCT1 was not involved in the MCT-mediated transport of phenolic acids.
- Bioscience, biotechnology, and biochemistry
Bioscience, biotechnology, and biochemistry 70(8), 1928-1933, 2006-08-23
Japan Society for Bioscience, Biotechnology, and Agrochemistry