The Study of the Transport Mechanism of Isorhynchophylline in Liver.

To investigate the transport mechanism of isorhynchophylline (IRN) by using the specific inhibitors of organic cation transporters (OCTs) and organic anion transporting polypeptides (OATPs) and attempt illustrate the metabolic mechanism of IRN in the liver. All animals were randomly divided into three groups: control group (only inject IRN), RIF group (inject IRN and rifampicin), and ADR group (inject IRN and adrenalone). The control group was injected with IRN via the caudal vein. The RIF group was injected with rifampicin (RIF) by gavage, and after 1 h, IRN was injected into the caudal vein. Similarly, the ADR group received adrenalone by the caudal vein, and after 0.5 h, IRN was injected into the caudal vein. Thereafter, blood samples were obtained by the heart punctures at 90 min, 180 min, and 300 min following drug administration. Rats were sacrificed at 300 min after drug administration; then, the liver tissue was harvested. The level of IRN was measured by using high-performance liquid chromatography (HPLC), and the Kp values were calculated. After RIF administration (OATPs inhibitors), the Kp value of IRN was slightly decreased when compared with that of the control group. Meanwhile, the Kp value of IRN was dramatically reduced compared to that of the control group following ADR administration (OCTs inhibitors). The results suggested that OCTs have mainly participated in the hepatic uptake process of IRN.