Clarification of organ specific transport mechanism of druge and its application to regulation of pharmacokinetics and pharmacodynamics

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The purpose of this research project is to clarify the organ specific transports of drugs from the view points of organ, cell, molecular and gene levels and to develop novel method for regulation of pharmacokinetics and pharmacodynamics of drugs. The following results were obtained by two years term of this research project consisted of 14 investigators :1.Several evidences were obtained for molecular and biological characteristics of transporters involved in the buccal and intestinal absorption and secretion, renal secretion and reabsorption, hepatic uptake and biliary secretion and in the brain influx and efflux transports. Cloning of transporters of PepT1, PepT2, MCT1, cMOAT,OAT-K1 and OCT2, their transport functions and tissue distribution were clarified. It was also clarified that P-glycoprotein functions as the transport barrier for lipophilic xenobiotics in the intestine and at the blood-brain barrier (BBB). Peptides were confirmed to be taken up by adsorptive-mediated endocytos … More is at the BBB to be delivered into the brain. 2.Improvement of absorption for drugs was achieved by glycosylation, endocytosis across Peyer's patches, iontophoretic method and by absorption enhancers to open tight junction. 3.Uptake of fractionated heparin by hepatocytes and Kupffer cells was clarified to be regulated by the scavenger receptor-mediated and plasma proteins-mediated mechanisms. Liver-specific delivery of drugs, proteins and gene was achieved by using galactosylated technology. Reactive oxygen species, such as superoxide and nitric oxide (NO), were clarified to play critical roles in the pathogenesis of various diseases. To overcome the oxidative stress, synthesized site-directed SOD derivatives were succeeded to deliver the targeting cells. An attractive approach for the antibody-based therapy of solid tumors was proposed and evaluated successfully by use of "vascular targeting" antibody to recognize tumor endothelial cells. 4.Using alpha 1-adrenoreceptor as a model, cloning of the receptors and detection of the tissue localization of the receptor protein were succeeded. It was indicated that uridine receptor plays some role not only in brain but also in peripheral tissues. Pharmacokinetic and pharmacodynamic behaviors for the transport in the brain, receptor binding and analgesic action were analyzed after peptazocine administration in rats. Less