The disposition of pravastatin in a rat model of streptozotocin-induced diabetes and organic anion transporting polypeptide 2 and multidrug resistance-associated protein 2 expression in the liver

The combination of diabetes and hyperlipidemia promotes the development of atherosclerosis. Therefore, it is important for diabetic patients to control blood fat. 3-Hydroxy-3-methylglutaryl enzyme A (HMG-CoA) reductase inhibitors (statins), like pravastatin, are frequently administered to diabetic patients for this purpose. Although the alterations of metabolic enzymes and transporters in the diabetic liver maybe change the disposition of pravastatin, the effect has not been fully investigated. In the present study, we investigated the disposition of pravastatin and the mRNA expression of transporters in the liver. Pravastatin (5 mg·kg−1 body weight) was administered intravenously to diabetic rats, and the pravastatin concentrations in the plasma, urine, and bile were measured by high-performance liquid chromatography. Changes in the mRNA expressions of multidrug resistance-associated protein 2 (MRP2) and organic anion transporting polypeptide 2 (OATP2) in the liver were also estimated using reverse transcriptase-polymerase chain reaction (RT-PCR). We found that the plasma pravastatin concentration was lower in the diabetic rat because the transportation of pravastatin into hepatocytes was promoted along with increased expression of OATP2. The biliary excretion ratio of pravastatin was significantly lower in the diabetic rat because the pravastatin transportation into bile was reduced along with the decreased expression of MRP2. To clarify these phenomena, the analysis of mRNA expression using real-time PCR and the measurement of the amount and the activity of proteins are necessary in future study.