3h atenolol

[³H]1-Methyl-4-phenylpyridinium (MPP) (specific activity (S.A.), 80 Ci/mmol) was purchased from Perkin-Elmer (Waltham, MA, USA); [³H]atenolol (S.A. 3.5 Ci/mmol) and [¹⁴C]metformin (S.A. 114 mCi/mmol) were purchased from Moravek Biochemicals (Brea, CA, USA). Unlabeled atenolol and metformin were purchased from Sigma-Aldrich (St. Louis, MO, USA) and AK Scientific (Union City, CA, USA), respectively; unlabeled MPP (purity > 99.5%) was synthesized by the Department of Chemistry and Biochemistry, University of Arizona. Ham’s F12 Kaighn’s modified medium was obtained from Sigma-Aldrich (Burlington, MA, USA). Other reagents were of analytical grade and obtained from standard sources.

[¹⁴C]Tetraethylammonium (TEA, 55 mCi/mmol) and [³H]1-methyl-4-phenylpyridinium (MPP⁺, 85 Ci/mmol) were obtained from American Radiolabeled Chemicals (St. Louis, MO, USA), [³H]atenolol (3.3 Ci/mmol) was from Moravek Biochemicals (Mercury Lane, Brea, CA, USA), and [³H]estrone-3-sulfate (54 Ci/mmol) was from PerkinElmer (Waltham, MA, USA). Unlabeled atenolol and Dulbecco’s modified Eagle’s medium (DMEM) were from Wako Pure Chemical Industries (Osaka, Japan). Fetal bovine serum (FBS) was obtained from Invitrogen (Carlsbad, CA, USA). All other regents were of analytical grade and commercially obtained.