@article {Kimura:February 2005:0724-8741:255,
	author = "Kimura, Naoko",
	author = "Okuda, Masahiro",
	author = "Inui, Ken-ichi",
	title = "Metformin Transport by Renal Basolateral Organic Cation Transporter hOCT2",
	journal = "Pharmaceutical Research",
	volume = "22",
	year = "February 2005",
	abstract = "Metformin, an antihyperglycemic agent, is eliminated by tubular secretion in addition to glomerular filtration in the human kidney. This study was performed to characterize metformin transport by human organic cation transporter 2 (hOCT2), the most abundant organic cation transporter in the basolateral membranes of the human kidney.<P></P>Accumulation of [<SUP>14</SUP>C]metformin was assessed by the tracer experiments in the human embryonic kidney (HEK293) cells expressing hOCT2.<P></P>The transport of [<SUP>14</SUP>C]metformin was markedly stimulated in hOCT2-expressing cells compared with the vector-transfected cells. The accumulation of [<SUP>14</SUP>C]metformin was concentrative and was dependent on the membrane potential, showing consistency with the characteristics of hOCT2. The apparent K<SUB>m</SUB> and V<SUB>max</SUB> values of [<SUP>14</SUP>C]metformin transport by hOCT2-expressing HEK293 cells were 1.38 &#177; 0.21 mM and 11.9 &#177; 1.5 nmol mg protein<SUP>-1</SUP> min<SUP>-1</SUP>, respectively. The order of the potencies of unlabeled biguanides to inhibit [<SUP>14</SUP>C]metformin transport by hOCT2 was phenformin &#062; buformin &#062; metformin. Furthermore, [<SUP>14</SUP>C]metformin transport was inhibited slightly or moderately by cationic drugs such as procainamide and quinidine at respective therapeutic concentrations.<P></P>Metformin is transported by the basolateral organic cation transporter hOCT2 in the human kidney. hOCT2 could play a role in the drug interactions between metformin and some cationic drugs.",
	pages = "255-259(5)",
	url = "http://www.ingentaconnect.com/content/klu/pham/2005/00000022/00000002/00001193"
	doi = "doi:10.1007/s11095-004-1193-3"
}