RT Journal Article SR Electronic T1 IMPAIRED RENAL EXCRETION OF 6-HYDROXY-5,7-DIMETHYL-2-METHYLAMINO-4-(3-PYRIDYLMETHYL) BENZOTHIAZOLE (E3040) SULFATE IN BREAST CANCER RESISTANCE PROTEIN (BCRP1/ABCG2) KNOCKOUT MICE JF Drug Metabolism and Disposition JO Drug Metab Dispos FD American Society for Pharmacology and Experimental Therapeutics SP 898 OP 901 VO 32 IS 9 A1 Mizuno, Naomi A1 Suzuki, Michiko A1 Kusuhara, Hiroyuki A1 Suzuki, Hiroshi A1 Takeuchi, Kenji A1 Niwa, Takuro A1 Jonker, Johan W. A1 Sugiyama, Yuichi YR 2004 UL http://dmd.aspetjournals.org/content/32/9/898.abstract AB Murine breast cancer resistance protein 1 (Bcrp1) is expressed in the brush-border membrane of proximal tubule cells of the kidney. The purpose of the present study is to investigate whether Bcrp1 could be involved in the urinary excretion of the human BCRP substrates, 6-hydroxy-5,7-dimethyl-2-methylamino-4-(3-pyridylmethyl) benzothiazole sulfate (E3040S) and 4-methylumbelliferone sulfate (4MUS), using Bcrp1(-/-) mice. E3040S and 4MUS were given to the mice by intravenous infusion, and plasma and kidney concentrations and the urinary excretion rate were determined. Knockout of Bcrp1 did not affect the creatinine clearance [7.17 ± 1.00 and 8.66 ± 2.02 ml/min/kg for Bcrp1(-/-) and wild-type mice, respectively]. The renal clearance of E3040S was 2.4-fold lower in Bcrp1 (-/-) mice compared with wild-type mice (2.74 ± 0.41 versus 6.55 ± 0.52 ml/min/kg). The concentration of E3040S in the kidney was increased in Bcrp1(-/-) mice compared with that in wild-type mice (55.5 ± 10.5 versus 19.4 ± 2.7 nmol/g kidney, respectively). In contrast, knockout of Bcrp1 did not affect the pharmacokinetic parameters of 4MUS, although 4MUS was predominantly excreted in the urine. This is to our knowledge the first demonstration of involvement of Bcrp1 in the renal secretion of organic sulfates. However, taking the results of 4MUS into consideration, the renal secretion of organic sulfates cannot be accounted for solely by Bcrp1, and transporters other than Bcrp1 are also involved. The American Society for Pharmacology and Experimental Therapeutics