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Recent functional studies have suggested that, in addition to simple diffusion, carrier-mediated transport may play an important role in foetal unconjugated bilirubin (UCB) uptake by the placenta. We have investigated the role of organic anion-transporting polypeptides (OATPs) in UCB transport by the placenta-maternal liver tandem. RNA was obtained from human liver (hL), human placenta (hPl) at term, and purified (> 80%) cytokeratin-7-positive mononucleated human trophoblast cells (hTCs). By analytical reverse transcription (RT)-PCR, agarose gel electrophoresis separation and sequencing, the mRNA of OATP-A ( SLC21A3 ) and OATP-8 ( SLC21A8 ) was identified in hL, hPl and hTCs, whereas that of OATP-C ( SLC21A6 ) was detectable only in hL. Real-time quantitative RT-PCR revealed that in hL the abundance of mRNA was OATP-8 > OATP-C >> OATP-A, whereas in hPl and hTCs this was OATP-8 >> OATP-A >> OATP-C. Expression levels for these OATPs were hL >> hTCs > hPl. Injection of mRNA of OATP-A, OATP-C or OATP-8 or RNA from hL, hPl or hTCs into Xenopus laevis oocytes conferred on them the ability to take up [(3)H]17 beta-D-glucuronosyl oestradiol ([(3)H]E(2)17 beta G) and [(3)H]UCB, although in the case of OATP-A mRNA, the induced uptake of [(3)H]UCB was very low. Cis -inhibition of [(3)H]E(2)17 beta G and [(3)H]UCB uptake by both unlabelled E(2)17 beta G and UCB was found in all cases. The affinity and efficiency of [(3)H]UCB transport was OATP-C > OATP-8. Kinetic parameters for [(3)H]UCB uptake induced by RNA from hTCs resembled most closely those of OATP-8. In conclusion, our results suggest that OATP-8 may play a major role in the carrier-mediated uptake of foetal UCB by the placental trophoblast, whereas both OATP-8 and OATP-C may substantially contribute to UCB uptake by adult hepatocytes.

In this study we sought to characterize a novel model of fulminant liver failure (FLF) by means of experimental infection of rabbits with the rabbit hemorrhagic disease virus (RHDV). Thirty-seven 9-week-old rabbits were injected intramuscularly with 2 x 10(4) hemagglutination units of an RHDV isolate. Eighty-five percent of rabbits died 36 to 54 hours after infection. From 36 hours after infection we noted marked increases in transaminases, lactate dehydrogenase, and total bilirubin. The rabbits exhibited hypoglycemia and coagulation abnormalities, with a significant decrease in factor V, factor VII, and prothrombin. Plasma aromatic amino acids and taurine showed progressive increases, and the Fischer index was significantly reduced. Expression of hepatocyte growth factor messenger RNA was inhibited from 36 hours after infection. Prostration and side recumbency were present at later stages, and neurologic symptoms rapidly progressed to coma. Onset of brain death was associated with a significant increase in intracranial pressure and blood ammonia. RHDV infection reproduces clinical, biochemical, and histologic features of the FLF syndrome and satisfies criteria for a suitable animal model. Rabbit hemorrhagic viral disease could provide a useful tool for the study of FLF and the evaluation of new liver-support technologies in human subjects.

We have determined the urinary 8-hydroxydeoxyguanosine (8-OHdG) levels of eight professional cyclists during a 4-day and a 3-week stage races. Monitoring of heart rates was used to establish zones corresponding to different intensities of exercise. The urinary 8-OHdG excretion, expressed by body weight, increased significantly in the first day or the first week of each race, respectively, and did not show further increases thereafter. Maximum 8-OHdG levels were reached in parallel to longer times spent at high intensities of exercise. Urinary excretion of creatinine increased with exercise, and changes in 8-OHdG levels were not detected when corrected by creatinine excretion. Serum glutathione concentrations did not change significantly at any point during exercise. We conclude that road cycling courses with an oxidative damage to DNA, which is sustained as long as the exercise is repeated. Both adaptation of antioxidant defenses and a decreased capacity to maintain a high intensity of effort may contribute to explain the absence of progressive increases in 8-OHdG excretion. The results of this study also confirm that the correction procedure using the amount of creatinine excreted should not be used when studying effects of exercise on urinary 8-OHdG.

This study was designed to investigate the effects of pectin on cholesterol and bile acid metabolism and to elucidate the mechanisms involved in its hypolipidemic effect in rats. The key regulatory enzymes in cholesterol and bile acid metabolism, 3-hydroxy-3-methylglutaryl-CoA reductase (HMG-CoA reductase) and cholesterol 7alpha-hydroxylase, were determined. Circulating, hepatic, and biliary lipid concentrations and fecal bile acid excretion were also measured. Male Wistar rats were fed a fiber-free or a pectin-supplemented (7 g/100 g) diet for 4 wk. Bile flow and the biliary secretion of both bile acids and cholesterol were not significantly different than controls in pectin-fed rats. The addition of pectin to the diet resulted in lower serum and liver cholesterol concentrations (-27 and -17%, respectively). Fecal bile acid excretion (+168%) and the hepatic activity of cholesterol 7alpha-hydroxylase (+70%) were significantly higher in pectin-fed animals. HMG-CoA reductase activity was also significantly greater (+11%) in the presence of dietary pectin. Results of our study indicate that pectin, by enhancing fecal bile acid excretion, may cause increased hepatic synthesis of bile acids and liver depletion of cholesterol in rats, which results in a higher rate of cholesterol synthesis and reduced serum cholesterol concentrations.

Background: Antipyrine clearance (CLAP) constitutes a sensitive indicator of hepatic microsomal enzyme activity providing specific information on hepatic function. The purpose of this study was to evaluate the influence of hypocaloric peripheral parenteral nutrition on CLAP in patients receiving nutrition support after elective surgery., Methods: CLAP was measured in 15 patients before elective gastrointestinal surgery and 6 days after the surgery. Antipyrine (1 g) was administered orally, and CLAP was determined by the one-sample method. Subjects received a postoperative 786 kcal/d regimen providing 66 g of amino acid per day and 133 g of glucose per day for 5 days. Nutritional status was evaluated by anthropometric parameters. A control group of 15 patients received no postoperative hypocaloric peripheral parenteral nutrition but received conventional fluid therapy., Results: Mean CLAP was increased by 61% (0.66 +/- 0.06 mL/min.kg-1 body wt vs 0.41 +/- 0.05 mL/min.kg-1 body wt in the preoperative period; p < .001), and antipyrine half-life was reduced by 42% (10.9 +/- 1.0 hours vs 18.9 +/- 2.0 hours; p < .001) after 5 days of hypocaloric peripheral parenteral nutrition. No significant modification was shown among control patients in CLAP (0.54 +/- 0.07 mL/min.kg-1 body wt vs 0.46 +/- 0.05 mL/min.kg-1 body wt in the preoperative period) or in antipyrine half-life (14.0 +/- 1.4 hours vs 16.5 +/- 1.8 hours). No significant correlation was observed between CLAP changes and those for the nutritional status of the patients., Conclusions: The results of our study indicate that oxidative drug-metabolizing capacity is increased in surgical patients maintained on hypocaloric peripheral parenteral nutrition. Clinicians should be conscious of the potential of this effect for altering the efficacy or toxicity of many therapeutic agents.

The effects of subclinical fasciolosis at various stages of its development on bilirubin metabolism were investigated in rats. Studies were carried out at 3 (initial lesions), 6 (parenchymal degeneration), and 11 weeks (biliary localization of the parasite) after infection with an oral dose of 20 metacercariae of Fasciola hepatica. Both bile flow and bile acid secretion were significantly reduced by Weeks 3 and 6 postinfection, while a significantly increased bile flow was found in the 11-week group. Serum concentration of unconjugated bilirubin was elevated at 3-6 weeks postinfection and that of conjugated bilirubin and the esterified/total bilirubin ratio increased in all infected rats. Biliary excretion of bilirubin mono- and diconjugates was maximally increased by 3-6 weeks, remaining elevated at 11 weeks. No significant change in the biliary diconjugate/monoconjugate ratio was found in any of the groups. UDP-glucuronosyltransferase activity was reduced by Weeks 3 and 6. This was accompanied by a significantly lowered liver cytochrome P450 concentration and an elevation in hepatic heme oxygenase activity. Blood hemoglobin concentration was significantly reduced and reticulocyte count increased by 6 and 11 weeks. Our results indicate that enhanced bilirubin production, cholestasis, and a reduced conjugating activity could be responsible for the changes in plasma and bile pigment composition during the acute stage of fasciolosis. Hemolysis and a high bilirubin excretion are maintained when the parasite migrates into the biliary ducts.

Proliferation of bile duct-like epithelial cells is a common feature of extrahepatic biliary obstruction and it is also present in other forms of liver disease. Experimental infestation with Fasciola hepatica induces hyperplasia of ductular cells together with different functional alterations, such as hypercholeresis, in the rat. We have investigated the contribution of ductular biliary secretion to the hypercholeretic phenomenon in rats with experimental fascioliasis. Infestation was induced by oral administration of 20 metacercariae of F. hepatica. Twelve weeks later, histological study of the liver showed a hyperplastic reaction with proliferation of bile duct-like structures. Basal bile flow in infested animals was significantly higher than that of control animals (+17%), while biliary secretion of bile acids did not significantly differ between both groups. Bile flow increase was associated in parasitized animals with a significantly lower [14C]mannitol bile:plasma ratio (-23%). Intravenous secretin administration (0.3 CU/100 g body wt min) induced a significant increase in the biliary concentration of bicarbonate (+21%) and an enhancement of bile flow (+21%) only in the animals with ductular proliferation. Taurocholate infusion (0.5 nmol/100 g body wt min) produced a similar bile flow increase both in control rats and in rats with proliferated biliary ductules. These results indicate that proliferated bile ductules and ducts spontaneously secrete bile in response to infestation by F. hepatica and that secretin-stimulated bile flow originates at the proliferated biliary structures.

1. Alterations induced by fascioliasis and cirrhosis on the biliary excretion of cefmetazole have been studied in Wistar rats. 2. Both infestation with Fasciola hepatica and experimental cirrhosis originated a significant decrease in the biliary excretion and in bile flow increase induced by the drug. 3. Administration of the beta-lactam antibiotic induced a lower degree of uncoupling of biliary lipid secretion in the cirrhotic and fasciolotic animals, but the effect was evident in all experimental groups.