Biomaterial Database

Primary active transport of pravastatin across the liver canalicular membrane in normal and mutant Eisai hyperbilirubinemic rats. 1996

M Yamazaki, and K Kobayashi, and Y Sugiyama

Faculty of Pharmaceutical Sciences, University of Tokyo, Japan.

We have previously demonstrated that the HMG-CoA reductase inhibitor pravastatin is efficiently taken up by the liver via the 'multispecific anion transporter' in an active manner. To further examine the fate of pravastatin within the liver, its biliary excretion was studied in a single-pass liver perfusion system and isolated liver canalicular membrane vesicles (CMVs) using normal (Sprague-Dawley rats; SDRs) and mutant Eisai hyperbilirubinemic rats (EHBRs). In the liver perfusion experiments, the outflowing drug concentration reached a steady state at 30 min and the extraction ratio was approximately 0.7 in both rat strains. Both the steady-state biliary excretion rate and bile flow rate of the EHBR group were 40% those of SDRs. At steady state, the fraction of unchanged drug in bile was 25-34% in both groups. The concentration ratios of unbound drug in cytosol versus that in sinusoid and in bile versus cytosol were, respectively, 11 and 87 in SDRs, and 13 and 94 in EHBRs. After correction for membrane potential (-40 mV in cytosol), the ratios became 49 and 19 in SDRs and 58 and 21 in EHBRs, respectively. The finding that all of these values were much larger than unity suggested that active transport occurred from liver to bile, as well as from plasma to liver, in both rat strains. Furthermore, ATP-dependent uptake of pravastatin was clearly observed in CMVs prepared from EHBRs as well as SDRs, whereas the stimulation by ATP of DNP-SG transport in CMV was observed only in SDRs. It was concluded that pravastatin is excreted into bile in high concentrations and a primary active transport mechanism which is maintained in EHBRs contributes to the biliary excretion of this drug.

UI	MeSH Term	Description	Entries
D008099	Liver	A large lobed glandular organ in the abdomen of vertebrates that is responsible for detoxification, metabolism, synthesis and storage of various substances.	Livers
D008297	Male		Males
D011922	Rats, Mutant Strains	Rats bearing mutant genes which are phenotypically expressed in the animals.	Mutant Strains Rat,Mutant Strains Rats,Rat, Mutant Strains,Strains Rat, Mutant,Strains Rats, Mutant
D004791	Enzyme Inhibitors	Compounds or agents that combine with an enzyme in such a manner as to prevent the normal substrate-enzyme combination and the catalytic reaction.	Enzyme Inhibitor,Inhibitor, Enzyme,Inhibitors, Enzyme
D006932	Hyperbilirubinemia	A condition characterized by an abnormal increase of BILIRUBIN in the blood, which may result in JAUNDICE. Bilirubin, a breakdown product of HEME, is normally excreted in the BILE or further catabolized before excretion in the urine.	Bilirubinemia,Bilirubinemias,Hyperbilirubinemias
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D001659	Biliary Tract	The BILE DUCTS and the GALLBLADDER.	Biliary System,Biliary Tree,System, Biliary,Tract, Biliary,Tree, Biliary
D001693	Biological Transport, Active	The movement of materials across cell membranes and epithelial layers against an electrochemical gradient, requiring the expenditure of metabolic energy.	Active Transport,Uphill Transport,Active Biological Transport,Biologic Transport, Active,Transport, Active Biological,Active Biologic Transport,Transport, Active,Transport, Active Biologic,Transport, Uphill
D013045	Species Specificity	The restriction of a characteristic behavior, anatomical structure or physical system, such as immune response; metabolic response, or gene or gene variant to the members of one species. It refers to that property which differentiates one species from another but it is also used for phylogenetic levels higher or lower than the species.	Species Specificities,Specificities, Species,Specificity, Species
D017035	Pravastatin	An antilipemic fungal metabolite isolated from cultures of Nocardia autotrophica. It acts as a competitive inhibitor of HMG CoA reductase (HYDROXYMETHYLGLUTARYL COA REDUCTASES).	Eptastatin,Apo-Pravastatin,Bristacol,CS-514,Elisor,Lin-Pravastatin,Lipemol,Liplat,Lipostat,Mevalotin,Nu-Pravastatin,Prareduct,Pravachol,Pravacol,Pravasin,Pravastatin Monosodium Salt, (6 beta)-Isomer,Pravastatin Sodium,Pravastatin Sodium Salt,Pravastatin tert-Octylamine Salt,Pravastatin, (6 beta)-Isomer,RMS-431,SQ-31,000,SQ-31000,Selektine,Vasten,Apo Pravastatin,CS 514,CS514,Lin Pravastatin,Nu Pravastatin,Pravastatin tert Octylamine Salt,RMS 431,RMS431,SQ 31,000,SQ 31000,SQ31,000,SQ31000,Sodium Salt, Pravastatin