Furosemide

LC-MS grade acetonitrile, methanol, and water were purchased from J.T. Baker (Milwaukee, WI, USA). Amlodipine, atenolol, atorvastatin, digoxin, enalapril, losartan, propranolol, simvastatin, and sulfameter were purchased from Sigma–Aldrich (St. Louis, MO, USA). Fenofibrate, furosemide, nifedipine, and valsartan were purchased from Tokyo Chemical Industry (Tokyo, Japan). Whatman 903 blood sampling cards were purchased from GE Healthcare (Westborough, MA, USA). Human whole blood with EDTA was purchased from Innovative Research (Novi, MI, USA), which is a supplier of human blood samples. Experimental usage of human blood was approved by the Institutional Review Board of Seoul National University (IRB NO. E1605/003-003).

C57BL/6JJcl mice receiving furosemide were assessed with ²³Na MRI. The diuretic effect was induced by injecting 10 mg/kg of furosemide (Tokyo Chemical Industry, Tokyo, Japan) into the murine tail vein. ²³Na MRI was performed before and 20 minutes after furosemide administration.