OCT2 and MATE1 provide bidirectional agmatine transport.
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Winter TN, Elmquist WF, Fairbanks CA
OCT2 and MATE1 provide bidirectional agmatine transport.
Mol Pharm. 2011 Feb 7;8(1):133-42. doi: 10.1021/mp100180a. Epub 2010 Dec 3.
- PubMed ID
- 21128598 [ View in PubMed]
- Abstract
Agmatine is a biogenic amine (l-arginine metabolite) of potential relevance to several central nervous system (CNS) conditions. The identities of transporters underlying agmatine and polyamine disposition in mammalian systems are not well-defined. The SLC-family organic cation transporters (OCT) OCT1 and OCT2 and multidrug and toxin extrusion transporter-1 (MATE1) are transport systems that may be of importance for the cellular disposition of agmatine and putrescine. We investigated the transport of [(3)H]agmatine and [(3)H]putrescine in human embryonic kidney (HEK293) cells stably transfected with hOCT1, hOCT2, and hMATE1. Agmatine transport by hOCT1 and hOCT2 was concentration-dependent, whereas only hOCT2 demonstrated pH-dependent transport. hOCT2 exhibited a greater affinity for agmatine (K(m) = 1.84 +/- 0.38 mM) than did hOCT1 (K(m) = 18.73 +/- 4.86 mM). Putrescine accumulation was pH- and concentration-dependent in hOCT2-HEK cells (K(m) = 11.29 +/- 4.26 mM) but not hOCT1-HEK cells. Agmatine accumulation, in contrast to putrescine, was significantly enhanced by hMATE1 overexpression, and was saturable (K(m) = 240 +/- 31 muM; V(max) = 192 +/- 10 pmol/min/mg of protein). Intracellular agmatine was also trans-stimulated (effluxed) from hMATE1-HEK cells in the presence of an inward proton-gradient. The hMATE1-mediated transport of agmatine was inhibited by polyamines, the prototypical substrates MPP+ and paraquat, as well as guanidine and arcaine, but not l-arginine. These results suggest that agmatine disposition may be influenced by hOCT2 and hMATE1, two transporters critical in the renal elimination of xenobiotic compounds.
DrugBank Data that Cites this Article
- Drug Transporters
Drug Transporter Kind Organism Pharmacological Action Actions Agmatine Solute carrier family 22 member 1 Protein Humans UnknownSubstrateDetails Guanidine Multidrug and toxin extrusion protein 1 Protein Humans UnknownSubstrateDetails