Urinary excretion of bile acids in bile duct-ligated rats.

Background: In patients with complete bile duct obstruction, the only pathway of bile acid elimination is through the urine. However, the urinary excretion of various bile acid conjugates in the presence of bile duct obstruction has not been clarified. Given this factor, the urinary excretion of various bile acids was compared in rats that were bile duct-ligated for 3 days.

Effects of lipopolysaccharide on the biliary excretion of bile acids and organic anions in rats.

Background: Lipopolysaccharide is known to be a cause of cholestasis associated with sepsis. It has also recently been reported to down-regulate the basolateral and canalicular transporters. The aim of the present study was to examine simultaneously the effect of lipopolysaccharide on the biliary excretion of typical substrates of bile salt export pump and multidrug resistance protein 2 in vivo, and the effect of lipopolysaccharide on the amount of these transporters.

Molecular action mode of Hippospongic acid A, an inhibitor of gastrulation of starfish embryos.

Hippospongic acid A (HA-A) is a novel natural triterpene metabolite that exhibits inhibitory activity against the gastrulation of starfish embryos isolated from a marine sponge, Hippospongia sp. We succeeded in chemically synthesizing the natural enantiomer and the racemate HA-A. In this study, we examined its action mode in vitro.

Inhibition of ileal bile acid absorption by colestimide.

Background: Colestimide is a new type of anion-exchange resin in Japan, but its effect on bile acid absorption in the ileum has not been studied.

Methods: Absorption of ursodeoxycholate, tauroursodeoxycholate, cholate, taurocholate and taurolithocholate-sulfate in rat ileum was compared in the presence and absence of colestimide. Bile acid adsorption by colestimide in vitro was also studied.

An advanced strategy of enhanced specific gene expression for hepatocellular carcinoma.

Alpha-fetoprotein (AFP) is a specific tumor marker for hepatocellular carcinoma (HCC). A gene expression system under AFP promoter/enhancer control would be specific for AFP producing cells, but its low expression level is a problem which must be overcome. For the purpose of AFP promoter enhancement, we constructed two recombinant adenoviral vectors; one containing the AFP promoter domain and transcriptional activator VP16LexA, and another the transcriptional activator binding site, the AFP promoter and the Cre gene.

Effect of dexamethasone on biliary excretion of bile acids and organic anions in rats.

Multidrug resistance protein 2 (Mrp2) is an important transporter for biliary excretion of organic anions, and is reported to be up-regulated by dexamethasone. In the present study, effect of dexamethazone (1 mg/kg) on biliary excretion of bile acids and organic anions was studied in rats. After bile duct cannulation, bile acids and organic anions were intravenously administered, and their biliary excretion was studied.

[The validity of serum acetaminophen concentration at 45 min as an index of gastric emptying rate: a study based on pharmacokinetic theories].

The reliability of the serum acetaminophen (APAP) concentration at 45 min (C45) as a measure of gastric emptying (GE) has been evaluated using a pharmacokinetic simulation work. The present results have revealed that C45 is a useful index to conveniently detect delayed GE, but it is unreliable to measure rapid GE. In addition, the following simple criteria for diagnosis of delayed GE has been proposed based on the pharmacokinetic theories: after ingestion of 20 mg/kg APAP dissolved in a 200 kcal-containing liquid meal, 1) the delayed GE is excluded when C45 > 5.

Hepatobiliary transport of bile acids and organic anions.

Recent studies have elucidated the mechanism and regulation of hepatic transport of bile acids and organic anions. Bile acids are taken up into hepatocytes by basolateral transporters, Na+-dependently by Na+/taurocholate cotransporting polypeptide (NTCP) and Na+-independently by organic anion transporting polypeptide (OATP) families. Organic anions are taken up into hepatocytes by OATP families.

Biliary excretion of taurolithocholate-sulfate and temocaprilat in cholestatic rats induced by bile duct-ligation and ethinylestradiol.

Down-regulation of multidrug resistance protein 2 (Mrp2), a major canalicular organic anion transporter, has been reported in various cholestatic models and in patients with cholestasis. In the present study, biliary excretion of taurolithocholate-sulfate and temocaprilat, substrates of Mrp2, was studied in bile duct-ligated rats and in cholestatic rats induced by ethinylestradiol (EE). Biliary excretion of temocaprilat was more markedly decreased in bile duct-ligated rats than that of taurolithocholate-sulfate.

Effect of ursodeoxycholate-3,7-disulfate on biliary excretion of lithocholate-3-O-glucuronide in Eisai hyperbilirubinemic rat (EHBR).

Biliary excretion of lithocholate-3-O-glucuronide and ursodeoxycholate-3,7-disulfate is markedly impaired in EHBR, in which the multidrug resistance protein 2 (Mrp2), a major ATP-dependent canalicular organic anion transporter, is impaired. We previously reported that biliary excretion of lithocholate-3-sulfate was enhanced by ursodeoxycholate-3,7-disulfate in Eisai hyperbilirubinemic rat (EHBR). In the present study, we examined the effect of ursodeoxycholate-3,7-disulfate infusion on biliary excretion of lithocholate-3-O-glucuronide.

Effects of phalloidin on the biliary excretion of cholephilic compounds in rats.

Phalloidin is known to cause cholestasis by preventing microfilament depolymerization. In addition, phalloidin is reported to inhibit the vesicular targeting of canalicular transporters. The aim of the present study was to examine the effect of phalloidin on the biliary excretion of substrates typical for various canalicular transporters in rats.

Effect of colestimide on absorption of unconjugated bile acids in the rat jejunum.

Background: Colestimide is a newly developed bile acid-binding resin in Japan, but its bile acid-binding properties have not been studied.

Methods: The absorption of unconjugated bile acids (5 mmol/L) in the ligated rat jejunum was compared in the presence and absence of colestimide. Furthermore, bile acid adsorption by colestimide was also studied in vitro.

Selective inhibition of the activities of both eukaryotic DNA polymerases and DNA topoisomerases by elenic acid.

(R)-(-)-Elenic acid (R-2,4-dimethyl-22-(p-hydroxyphenyl)-docos-3(E)-enoic acid) (EA) is a DNA topoisomerase II inhibitor found in an Indonesian sponge, Plakinastrella sp. We found and report here that it is a potent inhibitor of calf DNA polymerase alpha (IC(50)=7.7 microM) and rat DNA polymerase beta (IC(50)=12.

Transport activity of human MRP3 expressed in Sf9 cells: comparative studies with rat MRP3.

Purpose: Multidrug resistance-associated protein 3 (MRP3) was initially cloned as a hepatic transporter induced under cholestatic/ hyperbilirubinemic conditions. In the present study, transport property of human MRP3 (hMRP3) was compared with that of rat MRP3 (rMRP3).

Methods: Adenosine 5' triphosphate (ATP)-dependent uptake of several organic anions into the membrane vesicles isolated from the Sf9 cells expressing hMRP3 and rMRP3 was measured by rapid filtration technique.

Synthesis of (R)-(+)-hippospongic acid A, a triterpene isolated from the marine sponge, Hippospongia sp.

Hippospongic acid A (1) is a triterpene metabolite of the marine sponge, Hippospongia sp., with inhibitory activity against the gastrulation of starfish embryos. (R)-(+)-1 was synthesized by employing enzymatic kinetic resolution as the key step.

Effect of colestimide on intestinal absorption of ursodeoxycholic acid in men.

Colestimide is a new anion-exchange resin which is used to lower serum cholesterol levels in Japan. Because of its excellent compliance, colestimide can replace cholestyramine in the treatment of pruritus. However, there may be an interaction in cholestatic patients undergoing treatment with ursodeoxycholic acid (UDCA).

Synthesis of methyl (5Z,9Z,17R)-17-methylnonadeca-5,9-dienoate, the (R)-enantiomer of the structure proposed for a metabolite of the Philippine sponge Plakinastrella sp.

The (R)-enantiomer (1) of methyl (5Z,9Z)-17-methylnonadeca-5,9-dienoate, the structure proposed for a metabolite of the Philippine sponge, Plakinastrella sp., was synthesized. The 1H- and 13C-NMR spectra of the synthetic material were different from those reported for the natural product.

Biliary excretion of tauroursodeoxycholate-3-sulfate in the rat.

Biliary organic anion excretion is mediated by an ATP-dependent primary active transporter, multidrug resistance protein 2. On the other hand, a multiplicity of canalicular organic anion transport has been suggested. Ursodeoxycholic acid, the 7beta-epimer of chenodeoxycholic acid, is clinically used for various hepatobiliary diseases.

Does pheromone biology of Lambdina athasaria and L. pellucidaria contribute to their reproductive isolation?

Recently, 7-methylheptadecane and 7,11-dimethylheptadecane have been reported as sex pheromone components of both spring hemlock looper (SHL), Lambdina athasaria, and pitch pine looper (PPL), Lambdina pellucidaria. Our objective was to test the hypothesis that SHL and PPL are reproductively isolated, in part, through species specificity in: (1) absolute configuration of pheromone components, (2) diel periodicity of pheromonal communication, and/or (3) seasonal flight period. In coupled gas chromatographic-electroantennographic detection (GC-EAD) analyses of stereoselectively synthesized (7S)- and (7R)-7-methylheptadecane [7S; 7R] as well as (7S,11S)-, (7R,11R)-, and (meso-7,11)-7,11-dimethylheptadecane [7S,11S; 7R,11R; meso-7,11], only 7S and meso-7,11 elicited responses by male SHL and PPL antennae.

Synthesis and absolute configuration of Stellettadine A: a marine alkaloid that induces larval metamorphosis in ascidians.

Stellettadine A, a bisguanidinium alkaloid isolated from a marine sponge Stelletta sp. as an inducer of larval metamorphosis in ascidians, and its unnatural enantiomer were synthesized from the enantiomers of citronellal. The absolute configuration of stellettadine A was established as R.

Biliary excretion of phenolphthalein glucuronide in the rat.

To examine the substrate specificity of an ATP-dependent organic anion transporter, the multidrug resistance protein 2, we examined the effects of various bile acid conjugates and organic anions on the biliary excretion of phenolphthalein glucuronide, a hydrophilic glucuronide conjugate, in rats. Biliary phenolphthalein glucuronide excretion was markedly inhibited by taurolithocholate-3-sulfate and ursodeoxycholate-3-O-glucuronide. In contrast, ursodeoxycholate-3,7-disulfate and pravastatin only slightly inhibited and cefpiramide did not inhibit biliary phenolphthalein glucuronide excretion.

Biliary excretion of temocapril in zone 1- and zone 3-injured rat.

Temocapril is a prodrug of an angiotensin-converting enzyme inhibitor, temocaprilat, a substrate of multidrug resistance protein 2. Hepatocytes in zone 1 play a role in the uptake and biliary excretion of bile acids under physiological condition, and those in zone 3 may play a role only with their high-dose load. To investigate the pharmacokinetics of temocapril in liver injury, biliary excretion of temocapril was studied in zone 1- and zone 3-injured rats, caused by allyl alcohol and bromobenzene, respectively.

Synthesis of gibbilimbols A-D, cytotoxic and antibacterial alkenylphenols isolated from Piper gibbilimbum.

Gibbilimbols A [(E)-4-(4-decenyl)phenol, 1], B [(E)-4-(3-decenyl)phenol, 2], C [(E)-4-(4-octenyl)phenol, 3] and D [(E)-4-(3-octenyl)phenol, 4] were synthesized by coupling the phenolic parts with the alkyne parts and then reducing the triple bond of the resulting alkynylphenols. These alkenylphenols (1-4) are the cytotoxic and antibacterial constituents of the leaves of a medicinal plant (Piper gibbilimbum) that is used as a traditional medicine in Papua New Guinea.