Time course of cytochromes P450 decline during rat hepatocyte isolation and culture: effect of L-NAME.

The present work describes an isozyme-related effect of collagenase perfusion on hepatocyte microsomal cytochrome (CYP)-dependent monooxygenase activities: CYP 1A1/2-, 2B1/2-, 3A1/2- and 2E1-dependent activities in microsomes from rat hepatocytes after isolation were about 60% of that of liver microsomes, and CYP 4A1-dependent activity was equivalent to liver microsomes. In contrast, the microsomal protein content of the various CYP isoforms was not affected by hepatocyte isolation. This is in accordance with the hypothesis of CYP inactivation during the process of hepatocyte isolation by collagenase digestion. L-NAME (1 mM) was found unable to protect from the decline of CYP-dependent monooxygenase activities following hepatocyte isolation. It is possible that the decrease in glutathione peroxidase activity observed in the presence of L-NAME, namely depression of defense against peroxynitrite, could counteract the beneficial effect of L-NAME on nitric oxide synthesis inhibition. The present work also shows that L-NAME could not avoid the progressive, isoform-specific, most probably turnover-related, decline of CYP proteins and related monooxygenase activities in cultured hepatocytes. Dysregulations in the mechanisms of CYP expression in rat hepatocyte cultures, presently unknown but nitric oxide independent, thus appear to occur in cultured rat hepatocytes.

Clofibric acid or diethylmaleate supplemented diet decrease blood pressure in DOCA-salt treated male Sprague Dawley rats--relation with liver antioxidant status.

The effects of 8-week diethylmaleate (DEM) and clofibric acid (CFA) supplemented diet on blood pressure, body and liver weights, liver antioxidant status and nitric oxide synthase (NOS) activity were investigated in 8-week DOCA-salt treated and untreated Sprague-Dawley male rats. It appeared that DEM and particularly CFA treatments were associated with a significant decrease in blood pressure in DOCA-salt treated rats, and an accentuation of the decreases in body weights in both diet supplemented groups. This was not associated with increases in NO production in the liver. In contrast, hepatic lipid peroxidation was significantly decreased in both DOCA-salt treated and untreated groups on DEM and particularly on CFA supplemented diet. The protective effects of CFA and DEM against hepatic cellular damage could be involved in the decreases in blood pressure in DOCA-salt treated rats, where CFA was more efficient than DEM. In CFA supplemented groups, there was a strong increase in hepatic superoxide dismutase (SOD), glutathione-peroxidase (GSH-Px), and catalase (CAT) activities and in DEM supplemented groups, increases in SOD and CAT activities and in GSH levels were observed. Our data suggest that normalization of blood pressure in DOCA-salt treated rats by CFA was due to an enhancement of the half-life of NO while DEM increased its availability.

Antioxidant status, lipid peroxidation, mixed function oxidase and UDP-glucuronyl transferase activities in livers from control and DOCA-salt hypertensive male Sprague Dawley rats.

The effects of DOCA-salt hypertensive treatment on hepatic glutathione-dependent defense system, antioxidant enzymes, lipid peroxidation, mixed function oxidase and UDP-glucuronyl transferase activities were investigated in male Sprague Dawley rats. Compared with controls, DOCA-salt hypertensive rats had lower body weights (linked to liver hypertrophy). Mixed function oxidase and p-nitrophenol-UGT activities were not affected by the treatment but a significant lower rate of the glucuronoconjugation rate of bilirubin (p < 0.001) was observed in DOCA-salt hypertensive rats. While cytosolic glutathione contents and glutathione reductase activity were not affected, glutathione peroxidase (p < 0.001), glutathione transferase (p < 0.001) and catalase (p < 0.01) activities were decreased and associated with higher malondialdehyde contents (p < 0.001) in treated rats. The imbalance in liver antioxidant status (increasing generation of cellular radical species), associated with increases in lipid peroxidation, suggests that oxidative stress might be directly related to arterial hypertension in DOCA-salt treated male Sprague Dawley rats.

Acinar cells are target cells for androgens in mouse submandibular glands.

The variable coding sequence (VCS) multigene family encodes diverse salivary proteins, such as the SMR1 prohormone and the PR-VB1 proline-rich protein in the rat. In situ hybridization was used to study the cell-specific expression of two new mouse VCS genes, Vcs1 and Vcs2. We show that the Vcs1 transcripts, which code for a proline-rich protein, MSG1, are highly abundant in male and female parotid glands, in which they are specifically detected in acinar cells. No expression was seen in the submandibular or sublingual glands. In contrast, Vcs2 transcripts were found only in the acinar cells of the submandibular glands (SMGs) of male mice, in which they are expressed in response to androgens. Expression was found to be heterogeneous within acinar structures. No Vcs2 transcripts were detected in the SMGs of females or castrated males by Northern blot, RNase protection, or in situ hybridization. Androgen administration to females or castrated males induced expression at a level comparable to that of intact males. The Vcs2 gene is the first example of a mouse androgen-regulated gene that is expressed in SMG acinar cells. This result, in addition to our previous observation on SMR1 expression in rats, demonstrates that both acinar cells and granular convoluted tubule (GCT) cells are target cells for androgen action in rodent SMG.

Rifampicin and isoniazid increase acetaminophen and isoniazid cytotoxicity in human HepG2 hepatoma cells.

Acetaminophen (APAP) induced a concentration-dependent (0-30 mM) cytotoxic effect in human HepG2 hepatoma cells which was significantly increased when intracellular reduced glutathione (GSH) content was decreased. The cytotoxic effect of APAP (0-30 mM) was significantly lower in a day 3-treated compared to day 1-treated HepG2 cells. A 3-day preincubation of HepG2 cells with 5 microM 3-methylcholanthrene (3MC), 50 microM rifampicin (RFP) or 1 mM isoniazid (INH) significantly increased 15-30 mM APAP cytotoxicity, of about 15-20% for INH and RFP and 35-50% for 3MC. The cytotoxicity of 10 mM APAP was also increased (about 20%) by a 3-day preincubation with INH but was not affected by 3MC and RFP. INH induced a concentration-dependent (0-40 mM) cytotoxic effect in day-1 treated HepG2 cells and not significantly affected by decreases in intracellular GSH concentrations. INH was not cytotoxic in day 3-treated HepG2 cells. A 3-day preincubation of HepG2 cells with 50 mM RFP or 1 mM INH significantly increased 10-40 mM INH cytotoxicity, respectively of about 10% and 10-25%. A 3-day preincubation with 3MC did not modify the cytotoxic effect of INH at these concentrations. This is to our knowledge the first report of increases by INH and RFP of APAP of INH cytotoxicity in vitro in hepatocellular cells of human origin. It is in accordance with clinical observations of severe hepatotoxicity associated with APAP or INH usage in patients receiving multiple drug therapy (INH, RFP) for tuberculosis or in alcoholics.

Protective effect of anethol dithiolthione against acetaminophen hepatotoxicity in mice.

Anethol dithiolthione (ADT), usually prescribed as a choleretic drug, when given orally 1 hour prior to acetaminophen (AAP) (450 mg/kg intraperitoneally) in Swiss female mice, exhibited an hepatoprotective potency at doses as low as 10 mg/kg relative to serum aminotransferase activities and hepatic glutathione related enzyme system (glutathione reductase, peroxidase, transferase). These preliminary results are relevant with the use of pharmacologic dosage of ADT in hepatotoxicity prevention.

[Relationship between blood pressure level and different types of alcoholic beverages]. / Relation entre le niveau de pression artérielle et différents types de boissons alcooliques.

The relationship between alcohol consumption (AC) has been repeatedly confirmed. However, the respective contribution of the various types of beverages has not been clearly established. The cross-sectional data of the initial examination of the Paris prospective study II of the GREA, concerning 4547 male civil servants were thus analysed. Among subjects without any antihypertensive medication, systolic (SBP) and diastolic (DBP) blood pressure were positively associated with total AC; the differences between the first and the fifth quintile were respectively 6 and 3 mmHg (p less than 0.01 for wine, beer and spirits consumption). Using a linear combination of wine, beer and spirits consumption significantly improved the prediction of BP, as compared to total AC (p less than 0.001). In the multivariate analysis including age and body mass index (BMI), the consumption of 40 ml of alcohol from beer was associated with an increase of 5.7 mmHg for SBP and 2.6 mmHg for DBP (p less than 0.001). The elevation was 2.3 (SBP, p less than 0.001) and 0.8 mmHg (DBP, p less than 0.01) for wine consumption. Spirits consumption was associated with DBP (1.4 mmHg, p less than 0.001), but not with SBP. In conclusion, a positive relationship was observed with each of the three types of alcoholic beverages studied; however, this association was more pronounced for beer than for the two other beverages.

Relationship between sex hormones and haemostatic factors in healthy middle-aged men.

Associations of plasma testosterone and estradiol with some haemostatic factors (factor VII activity, fibrinogen, antithrombin III and alpha 2-antiplasmin) were cross-sectionally examined in 251 healthy, middle-aged men participating in the Paris Prospective Study II on risk factors for ischaemic heart disease. Testosterone levels were negatively correlated to factor VII activity and alpha 2-antiplasmin, the main inhibitor of fibrinolysis. No association was found either between testosterone levels and both fibrinogen and antithrombin III, or between estradiol levels and the set of haemostatic variables. The associations between testosterone and both factor VIIc and alpha 2-antiplasmin were independent of HDL-cholesterol, LDL-cholesterol, triglycerides, smoking, alcohol, body mass index and blood pressure. These results suggest that low circulating testosterone levels might be associated with a hypercoagulability state and therefore could contribute to an increased risk of IHD.

An epidemiologic appraisal of the associations between the fatty acids esterifying serum cholesterol and some cardiovascular risk factors in middle-aged men.

The relations between the fatty acids of cholesterol esters and some cardiovascular risk factors have been investigated in a sample of 3,348 middle-aged men examined at entry into the Paris Prospective Study 2. The partial associations between the risk factors and the various fatty acids have been evaluated using a special regression method that takes into account the structural dependencies among the percentages of fatty acids. The results show that palmitoleic acid is strongly associated with alcohol consumption and blood pressure and that its association with blood pressure is absent in nondrinkers. High density lipoprotein cholesterol and apolipoprotein A1 are negatively associated with palmitic and dihomogammalinolenic acids and positively associated with oleic and linoleic acids. An inverse relation of low density lipoprotein cholesterol and apolipoprotein B to these fatty acids is also observed. Simultaneous high levels of palmitic and dihomogammalinolenic acids and low levels of oleic and linoleic acids could then be related to profiles of lipids and apolipoproteins exposing one to a high risk of coronary heart disease. These associations may be of interest in interpreting the relations observed in other studies between the fatty acid composition of cholesterol esters or other lipids and coronary heart disease.

[Determination of total serum triiodothyronine in hyperthyroidism: comparison of fluorescence polarization and immunoenzymology]. / Dosage de la triiodothyronine sérique totale dans les hyperthyroïdies: comparaison de la polarisation de fluorescence et de l'immunoenzymologie.

We evaluated the performances of the Abbott fluorescence polarization assay (FPIA) utilizing the TDx system for human total triiodothyronine (T3) in hyperthyroidism. We compared the results with an immunoenzymometric assay (IEA) (Enzymum Test T3 Boehringer-Mannheim). Greatest attention was focused on the diagnosis of hyperthyroidism because detection of subclinical hyperthyroidism is important. The repeatability of the Abbott fluorescence polarization assay was satisfying (m = 8.07 +/- 0.37 nmol.l-1, CV = 4.59%). The reproducibility was tested with Abbott control sera: m = 4.58 +/- 0.53 nmol.l-1 and CV = 11.5 per cent for level M; m = 7.95 +/- 0.66 nmol.l-1 and CV = 8.23 per cent for level H; m = 2.38 +/- 0.39 nmol.l-1 and CV = 16.5 for level L. The correlation of results of the Abbott assay with those of the Boehringer assay was good for samples from hyperthyroid patients. Values for hyperthyroid and euthyroid subjects were resolved slightly better with the Abbott FPIA than with Boehringer IEA. The Abbott total T3 fluorescence polarization assay may have an additional role to play in monitoring thyroid function in patients under iodine treatment (amiodarone) to eliminate a secondary hyperthyroïdism.

Relation of parental history of early myocardial infarction to the level of apoprotein B in men.

The relations between parental history of early myocardial infarction and plasma lipids and apoproteins have been examined in a population of 4045 middle-aged (20 to 60 years old) working men at the initial examination of the Paris Prospective Study 2. Subjects with a history of myocardial infarction, angina pectoris, or peripheral arterial disease or those treated with hypolipidemic drugs were excluded from the analysis. The numbers of subjects with a paternal or maternal history of early myocardial infarction were 123 and 30, respectively. After adjustment for age, cigarette consumption, alcohol consumption, and body mass index, subjects with parental history of myocardial infarction had higher levels of total cholesterol (p less than .01), low-density lipoprotein (LDL) cholesterol (p less than .01), and apoprotein B (APOB) (p less than .0001) and a lower level of high-density lipoprotein (HDL) cholesterol (p less than .05) than subjects with no parental history of myocardial infarction. On the other hand, apoprotein A1 (APOA1) and triglyceride levels were not different between the two groups. The ratios of HDL/total cholesterol and APOA1/APOB were also lower in presence of parental myocardial infarction (p less than .001 and p less than .01, respectively). When a discriminant analysis was performed, only APOB level was related to parental myocardial infarction. The results for paternal and maternal history were very similar and were grouped for the analysis. We conclude that part of the known relationship between parental history of myocardial infarction and coronary heart disease could be mediated by an increased APOB level.

Ultrastructural changes in the parenchymal liver cells of rats treated with high doses of rifampicin.

Ultrastructural study of hepatic parenchyma was carried out in female Wistar rats after they had received high doses (400 mg X kg-1) of rifampicin for 1, 2, 4, 6 and 8 days. Morphological changes in the endoplasmic reticulum, Golgi apparatus and mitochondria were observed as early as day 1 of intoxication. These changes corroborate the biochemical data available regarding RFP-induced fatty liver.

Body mass, blood pressure, glucose, and lipids. Does plasma insulin explain their relationships?

Obesity, hypertension, a high plasma level of glucose, and some lipid abnormalities (high plasma levels of cholesterol and triglycerides) often occur in the same individuals. Some authors have postulated that the elevated levels of plasma insulin in obese individuals may explain this association. To explore this hypothesis further, the relationships between body mass index, fasting plasma glucose and insulin, blood pressure, serum lipids, and apoproteins were investigated in a group of 2144 healthy middle-aged men. Analysis of the data show that the associations between body mass index and blood pressure or lipid variables are largely independent of plasma glucose and insulin. Plasma glucose is strongly related to blood pressure in nonobese subjects. Plasma insulin is not associated with blood pressure independently of body mass index and plasma glucose; however, the simultaneous elevation of body mass index, plasma glucose, and insulin is strongly associated with blood pressure. The results also confirm that plasma insulin is positively related to triglycerides and negatively related to high density lipoprotein cholesterol independently of plasma glucose and body mass index.

Is the level of serum triglyceride a significant predictor of coronary death in "normocholesterolemic" subjects? The Paris Prospective Study.

Since the relation between serum triglyceride level and coronary heart disease after adjustment for cholesterol and other risk factors remains controversial, the authors have tested the hypothesis that it could be different according to the level of serum cholesterol, i.e., that there may be an interaction between cholesterol and triglyceride level in prediction of coronary heart disease risk. The data of the Paris Prospective Study were used to carry out a survival analysis, by using the Cox model, with coronary heart disease death as the end point and triglyceride and different risk factors as the predictor variables. In this study, during a mean follow-up of 11.4 +/- 2.2 years, 157 coronary heart disease deaths occurred. Serum triglyceride level is not an independent predictor of coronary heart disease death after adjustment for serum cholesterol. However, when cholesterol, triglyceride, and their interaction term are introduced in the regression equation, all variables contribute significantly to the risk. This is also true when other risk factors are taken into account. As a consequence of this interaction, among the 3,585 subjects with a serum cholesterol level lower than 220 mg/100 ml, serum triglyceride level is an independent predictor of risk, even after adjustment for all other risk factors.

Thyroxine-binding prealbumin, overnutrition and apolipoprotein A1.

Thyroxine-binding prealbumin (TBPA) seems to be more useful than other biochemical markers for the detection of subclinical protein-energy malnutrition. Accordingly, one can question whether its sensitivity to nutritional supply could be used in healthy populations for the discrimination of groups with low or high energy intakes; if such were the case, could TBPA serve as an index of overnutrition? In order to answer these questions, we measured TBPA circulating levels in three groups of healthy French subjects from a working population, with relatively low, medium or high levels of energy intake. We also observed the correlations of this protein with nutrient intakes and with some biological parameters related to the general nutritional status of the subjects. The observed figures did not support the hypothesis that TBPA could be used to discriminate healthy subjects with relatively low or high energy intake nor as an index of overnutrition. This study disclosed a positive relation of TBPA with alcohol consumption and related parameters such as body mass index or gamma-glutamyl transferase as well as a negative one with alpha 2-globulin and gamma-globulin. Other investigators have found similar results in chronic alcoholics, surgical patients, or patients suffering from severe illnesses such as cancer. Here, the study population consisted of adult men, neither undernourished nor suffering from any severe pathology and who could not be considered excessive drinkers. Positive relations were also observed between TBPA and apolipoprotein A1 and HDL cholesterol levels, which are negatively associated with coronary heart disease risk.

[Arterial pressure, obesity and fat and alcohol consumption]. / Pression artérielle, corpulence et consommation de graisse et d'alcool.

The baseline data of 2 500 subjects included in the Paris Prospective Study II were used to explore the relationship between the frequency of hypertension and some variables closely linked to the diet. These variables are: body mass, alcohol consumption and the proportion of linoleic acid (C18:2) in the plasma cholesterol esters; the latter variable being used as a marker of dietary intake of linoleic acid. The results show, after adjustment on age and the presence of an antihypertensive treatment, a significant independent relationship between these factors and the frequency of hypertension. The adjusted relative frequency of hypertension is 1, 1.4 and 2.5 in the tertiles of increasing corpulence; 1, 1.2 and 1.7 in the tertiles of increasing alcohol consumption and 1, 0.6 and 0.8 in the tertiles of increasing C18:2. Furthermore, among the 263 subjects belonging simultaneously to the higher tertiles of corpulence and alcohol consumption and to the two lower tertiles of C18:2, the number of hypertensive subjects is 58 (22 p. 100 whereas among the 2 236 remaining subjects, 164 are hypertensives (7 p. 100). These results suggest that hypertension is frequently linked to dietary factors.