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MicroRNAs (miRNAs) are small non-coding RNAs that are involved in mRNA post-transcriptional regulation. The deregulation of miRNAs affects the expression of drug-metabolizing enzymes, drug transporters, and nuclear receptors, all of which are important in regulating drug metabolism. miRNA expression can be altered by several endogenous or exogenous agents, such as steroid hormones, carcinogens, and therapeutic drugs. However, it is unclear whether hepatic miRNA expression is regulated by nuclear receptors, such as pregnane X receptor (PXR) and constitutive androstane receptor (CAR), which are indispensable for the expression of the CYPs. Here we investigated the effects of the mouse PXR and CAR ligands pregnenolone-16α-carbonitrile (PCN) and 1,4-bis[(3,5-dichloropyridin-2-yl)oxy]benzene (TCPOBOP) on hepatic miRNA expression in mice. We found that the expression of 9 miRNAs was increased (>2-fold) and of 4 miRNAs was decreased (>50%) in response to PCN, while TCPOBOP treatment led to the up-regulation of 8 miRNAs and down-regulation of 6 miRNAs. Using several miRNA target prediction algorithms, we found that the predicted target genes included several lesser known Cyp genes (Cyp1a1, Cyp1b1, Cyp2b10, Cyp2c38, Cyp2u1, Cyp4a12a/b, Cyp4v3, Cyp17a1, Cyp39a1, and Cyp51). We analyzed the expression of these genes in response to PCN and TCPOBOP and found changes in their mRNA levels, some of which were negatively correlated with the expression of their corresponding miRNAs, suggesting that miRNAs may play a role in regulating Cyp enzyme expression. Further studies will be required to fully elucidate the miRNA regulatory mechanisms that contribute to modulating CYP expression.

Certain physiological states and diseases can alter the expression and activity of cytochrome P450 s (CYPs), which have the potential to cause unexpected adverse effects. We previously demonstrated that lipopolysaccharide (LPS)-induced inflammation attenuates the induction of CYPs by xenobiotics in mouse liver. In this study, to investigate whether anaphylaxis-induced inflammation affects the hepatic CYPs' expression, we examined the effects of ovalbumin (OVA)-induced anaphylaxis on constitutive CYP mRNA and protein expressions. We also compared these effects with those obtained with LPS treatment. In addition, we examined the tumor necrosis factor (TNF) alpha and interleukin (IL)-113 mRNA levels, because these cytokines are known to be induced by LPS treatment and anaphylactic reactions. LPS treatment decreased the constitutively expressed Cyp1a2, Cyp2c29, and Cyp3al 1 mRNAs, and increased the TNFalpha and IL-1beta mRNAs. LPS treatment also decreased the CYP1A2 and CYP3A protein levels. Anaphylaxis, on the other hand, did not change the levels of the constitutively expressed Cyp1a2, Cyp2c29, or Cyp3a1 1 mRNAs, although it increased the TNFalpha and IL-1beta mRNAs, as observed in the LPS-treated mice. These results suggest that anaphylaxis-induced inflammation had less effect than LPS-induced inflammation on these CYPs in the liver. In contrast, we observed that the expressions of Cyp2b10 mRNA and its protein were quite different from those of the other CYPs in both the anaphylactic and LPS-treated mice. Our findings strongly suggest that the alteration of the constitutive CYPs' expression levels during inflammation varies according to the immunostimulation pathway.

Hepatic dysfunction is one of the critical complications in acute pancreatitis but this mechanism is poorly understood. In patients with acute pancreatitis, hypoalbuminemia is often recognized, suggesting possible disturbance of hepatic transport of proteins and hepatic metabolites. The present study was undertaken to elucidate hepatic function in cerulein-induced pancreatitis from the viewpoint of intrahepatic vesicular transport. We examined the biliary excretion of lipopolysaccharide (LPS), whose pathway in the hepatocyte has been shown to be microtubule dependent. In vivo studies and ex vivo studies using isolated perfused rat liver (IPRL) showed that cumulative excretion of LPS in each period was significantly reduced, by 49 and 25%, respectively, compared with that in control rats. But studies of biliary secretion in vivo and ex vivo studies indicated statistical insignificance between the two groups. Moreover, biliary excretion of LPS was inhibited to 60% of the control by colchicine pretreatment, without affecting bile flow in IPRL, but gadolinium chloride had no effect. We conclude that transport of LPS across the hepatocyte from blood to bile is impaired in rats with cerulein-induced pancreatitis without being affected by Kupffer cell function. These results suggest that a disturbance of vesicular transport in hepatocyte may also occur in exocytosis and endocytosis via the sinusoidal membrane, cause impairment of hepatic transport of proteins and hepatic metabolites, and result in hepatic dysfunction in acute pancreatitis.

Intra-arterial infusion liver scintigraphy was performed in 11 patients with primary or metastatic liver tumor, and intraportal infusion liver scintigraphy was performed in 6 patients for prophylaxis of liver metastasis from colorectal cancer. 99mTc-Sn colloid or 99mTc-phytate was administered through the catheter of which tip was placed in the portal vein or the hepatic artery, and then liver image was obtained. When 99mTc-phytate was infused intra-arterially, significant amount of the infused tracer passed through the liver and we could not get sufficient information to assess the distribution of drug administered through the catheter. On the other hand, intraportal infusion liver scintigraphy using 99mTc-Sn colloid or 99mTc-phytate and intra-arterial infusion liver scintigraphy using 99mTc-Sn colloid revealed heterogeneity of liver uptake, tracer uptake in spleen, low uptake area corresponding to the liver tumor and high uptake area around it. The findings will be clinically useful, and these methods are thought to be helpful to confirm the satisfactory drug distribution.

The effect of sodium picosulfate was examined in liver cell cultures of rabbit, rat and man exposed to substance concentrations of 25, 50, 100, 200, 400, 800 and 1600 micrograms/ml. At 400, 800 and 1600 micrograms/ml the rapidly growing cultured liver cells of rabbit showed dose-dependently vacuolic and fatty change as well as necrosis combined with a lowered mitotic activity and a slight increase in LDH values in the medium at 800 and 1600 micrograms/ml. Comparable but less severe effects were observed in 4-day old liver cell cultures of rat, while liver cells cultured for 6 to 11 days tolerated 1600 micrograms/ml sodium picosulfate. In human liver cultures the number of cells was slightly lowered at 800 and 1600 micrograms/ml and the number of nuclei in division was decreased dependent on dose.

The circadian rhythm of liver weight and hepatic structures was studied in rats given a maximum tolerated dose of 70 or 80 mg/kg/day Phenobarbital during 7 days and killed at four different hours of the following day. The drug-induced increase in liver weight in % of body weight of rats was about 1% in the morning and in the afternoon in comparison with controls. At 6.00--7.00 during the glycogen maximum, the fine structure of hepatocytes was normal except enlargement and glycogen depletion of cells in the near neighbourhood of central veins. From 9.00--10.00 the mitotic activity was markidly increased and parallel to the progressive disappearance of glycogen the smooth endoplasmic reticulum (SER) became prominent. Hypertrophy of SER was fully developed at 15.00--16.00 and 17.00--18.00.

The circadian rhythm of gastric content, serum alkaline phosphatase (alk.P.), serum lipids, body weight (wt), relative (rel.) liver wt, cellular structures (by light- and electron-microscopy), mitotic activity of hepatocytes, glycogen content, protein and lipids in liver was studied in 180 male Sprague-Dawley rats orally treated at 0830-1030 with 50 mg/kg phenobarbital (PB) for 7 days. Thereafter, five PB-treated males and five controls each were studied at 4-hr intervals at 0600, 1000, 1400, 1800, 2200 and 0200 on 3 consecutive days. The lighting schedule in the colony was 12:12 = light/dark (light from 0600 to 1800). Following the rhythm of gastric emptying, the rel. liver wt showed a clear circadian rhythm with a peak at 0800. The rel. liver wt was raised in PB-treated rats at all times of the day. The circadian rhythm of cellular structures was closely related to the hepatic glycogen content which exhibited a clear rhythm with the peak also at 0800, but lowered values were found in PB-treated rats. The mitotic activity of hepatocytes was significantly increased in PB-treated rats but displayed the same circadian rhythm as controls with peaks at noon and troughs at midnight. The well-known hypertrophy of the smooth endoplasmic reticulum in PB-treated rats was not found at 0600, but was fully developed at 1400 and 2200. PB-treatment increased significantly the liver content of cholesterol, triglycerides and phospholipids. Liver cholesterol showed a clear circadian rhythm with peaks at 1800. No rhythm of liver protein, triglycerides and phospholipids was observed. In serum, levels of cholesterol were significantly elevated, those of triglycerides and alk.P. significantly lowered, while those of phospholipids were not affected by the treatment. The three serum lipids, alk.P. and beta-lipoprotein exhibited a clear circadian rhythm, while serum glucose and non-esterified fatty acids did not.

The influence of Dipyridamole on acute hepatotoxicity has been studied in male SD-JCL rats doses with carbon tetrachloride. High single oral doses of Dipyridamole lowered the serum enzyme activity and reduced significantly the area % of hepatic necrosis and hydropic degeneration, but not of steatosis. Dipyridamole was effective from 1 hr before through 6 hrs after the oral administration of CCl4. Doses below 1,000 mg/kg Dipyridamole were less effective. No delay in the onset of CCl4-induced liver damages was observed. Dipyridamole was also effective when CCl4 toxicity was enhanced by isopropanol.

The circadian rhythm of hexobarbital sleeping time and lipids content in liver and serum were studied in 226 male Sprague-Dawley rats pretreated daily at 0800-0900 with 70 mg/kg (study 1 or 3) or 50 mg/kg (study 2) phenobarbital (PB) orally for 7 days. Thereafter, eight (study 1) or five (study 2 and 3) rats each were studied at 4-hr intervals at 1000, 1400, 1800, 2200, 0200, 0600 and 1000 through the following day. The lighting schedule in the colony was 12:12 +/- light:dark (light from 0600 to 1800). The hexobarbital sleeping times of PB-pretreated rats were generally shortened compared to the controls and no circadian rhythm was observed. PB-treatment increased slightly the liver content of cholesterol, and significantly that of triglycerides and phospholipids. Liver cholesterol and phospholipids showed circadian rhythms with peaks during the dark phase. No circadian rhythm of liver triglycerides existed. In serum, levels of triglycerides and phospholipids were slightly lowered by PB-treatment, while levels of cholesterol and beta-lipoprotein were not influenced. Serum values did not exhibit circadian rhythms.

Cultured liver cells of man, rat and rabbit were exposed to sodium picosulfate using medium concentrations of 400, 800,1000,1600, or 2000 micrograms/ml, and the results were compared with findings after bisacodyl at 25, 50 or 100 micrograms/ml and sennoside at 100 or 200 micrograms/ml. Much higher concentrations of sodium picosulfate than of both comparative substances were tolerated. At the doses used, hepatocytes of rabbit were slightly more sensitive against sodium picosulfate, while effects of bisacodyl and sennoside on hepatocytes were comparable between the three species used. No substance-related deviations in leakage of LDH from liver cells into culture medium were observed. The protein content was lowered in liver cells of rabbit exposed to 1600 micrograms/ml sodium picosulfate and the human cells exposed to 100 micrograms/ml bisacodyl. An increase in spindle-shaped growth occurred only in human cells exposed to bisacodyl.

The purpose of this study is to evaluate the clinical efficacy of liver SPECT (single photon emission computed tomography). Eleven hospitals which are in or near Tokyo are participating in this study. Planar liver images and SPECT images of 134 cases which were retrospectively confirmed for its final diagnosis were collected. At the first study, the planar images (PS) were read by 13 nuclear medicine physicians. The second, the image reading by the combination of the planar images and the SPECT images (PS + SPECT) were performed. The confidence level of diagnosis for SOL (space occupying lesion) obtained by the image reading of PS and PS + SPECT has been analyzed by using the SOL detection model. The SOL detectability of PS + SPECT was higher than that of PS only. However, these differences were not statistically significant.

The purpose of this study is to evaluate the clinical efficacy of liver SPECT (single photon emission computed tomography). The two examinations were performed in 76 cases with SOL (space occupying lesion) and 58 normal cases. The results of the image reading by the planar image only (PS) and that of the image reading by the combination of PS and SPECT (PS + SPECT) were analyzed by ROC (receiver operating characteristic) analysis. The ROC curves showed that SPECT appears to reduce the number of results which were equivocal by the image reading of PS only. The detectability of SPECT for SOL in the left lobe of liver was less than that of PS without statistical significance. However, the performance of SPECT for SOL in the right lobe of liver was significantly better than that of PS.

The purpose of this study is to evaluate the clinical efficacy of the liver SPECT about detectability of SOLs (space occupying lesion). The images were interpreted with the planar scintigram (PS) only and combination of PS and SPECT (single photon emission computed tomography) by 11 physicians. Changes of false positive and false negative rate were calculated to evaluate the influence of the diffuse parenchymal liver disease and the localization of the SOLs. Addition of SPECT to PS in the cases who are suspected SOLs is effective in right hepatic lobe (right anterior and posterior segment) to detect the SOLs, but not effective in left lateral segment. Addition of SPECT to PS in the cases with diffuse parenchymal liver disease and SOLs increases the false positive rate.

The circadian rhythm of the liver, namely organ weight, cellular structures (by light-microscopy), glycogen content (by periodic acid-Schiff (PAS) reaction) and mitotic activity, was studied in 166 male Sprague-Dawley rats orally treated daily at 0800-0900 with 70 (study 1) or 50 (study 2) mg/kg phenobarbital (PB) for 7 days. Thereafter, eight (study 1) or five (study 2) rats each were studied at 4-hr intervals at 1000, 1400, 1800, 2200, 0200, 0600 and 1000 through till the following day. The lighting schedule in the colony was 12:12, light:dark (light from 0600 to 1800). The liver weight was raised in PB-treated rats at all times of the day compared to controls and showed a distinct circadian rhythm with a peak at 1000 and a minimum at 2200 in PB-treated rats and the controls. The circadian rhythm of cellular structures was closely related to the hepatic glycogen content which was in good agreement with the controls, but at 1400 and 1800 the glycogen particles were more distinctly diminished in the enlarged centrilobular hepatocytes of PB-treated rats. The mitotic activity of hepatocytes was markedly increased in rats treated with PB but showed the same circadian rhythm as controls with a peak at 1000.

A series of novel synthetic monohydroxy polychlorinated biphenyls (OH-PCBs) (5 trichloro-, 5 tetrachloro- and 5 pentachloro-compounds) have been characterized (1H and 13C NMR and high resolution MS) and their estrogenic and thyroid hormone activities assessed using a yeast two-hybrid assay, both with and without possible metabolic activation by rat liver S9 preparation. Moderate estrogenic activity was found for 2,3,4′-trichlorobiphenyl-4-ol (compound 5) but this was eliminated when exposed to the S9 mix. 2,2′,3′,4,6-Pentachlorobiphenyl-3-ol (13) and 2′,3,3′,6-tetrachlorobiphenyl-4-ol (10) both showed weak estrogenicity in the absence of the S9 mix. The estrogenicity of compound (10) was enhanced 10-fold by exposure to S9 metabolic activation but that of compound (13) remained unchanged. 2′,4,5′,6-Tetrachlorobiphenyl-2-ol (6) showed strong thyroid hormonal activity (5% of that of T4) whereas 3′,4,6-trichlorobiphenyl-3-ol (4), compound (10) and 2,3′,4,5′,6-pentachlorobiphenyl-3-ol (14) showed moderate activity, and 2′,3,3′,5-tetrachlorobiphenyl-2-ol (8) and 3,3′,5,5′,6-pentachlorobiphenyl-2-ol (11) showed weak activity. The activity of (4) was eliminated by S9 metabolic activation whereas those of (6) and (14) were weakened and that of (10) remained unchanged. [Copyright &y& Elsevier]