Porcine hepatocyte-Kupffer cell co-culture as an in vitro model for testing the efficacy of anti-inflammatory substances

As Kupffer cells are highly involved in the regulation of hepatic inflammatory response, the main goal of this study was to improve and to characterize a hepatocyte-Kupffer cell co-culture of pig origin for modelling endotoxin-induced hepatic inflammation and for testing the efficacy of potential anti-inflammatory substances. This monolayer co-culture was prepared from primary isolated swine hepatocytes and Kupffer cells in the ratio of 6:1 and 2:1, mimicking different states of liver inflammation. The prepared cell cultures were characterized by immunohistochemical CD-68 detection. Lipopolysaccharide (LPS) challenge of both co-cultures resulted in elevated interleukin-8 (IL-8) and that of 6:1 co-cultures in increased IL-6 production with a higher extent than on hepatocyte monocultures, justifying the key role of Kupffer cells in pro-inflammatory cytokine production. LPS-induced IL-8 production was successfully attenuated by concomitant application of both sodium butyrate and terpinen-4-ol on hepatocyte monocultures, but not on co-cultures, demonstrating the importance of the presence of Kupffer cells in cell cultures as inflammatory models. Based on these initial data, the applied porcine primary hepatocyte-Kupffer cell co-culture is suggested to be a proper tool for in vitro investigations on liver physiology and hepatic inflammation in pigs and can be used as a useful model mimicking in vivo conditions in veterinary research.

Feed-drug interaction of orally applied butyrate and phenobarbital on hepatic cytochrome P450 activity in chickens

The expression of hepatic drug-metabolizing cytochrome P450 (CYP) enzymes may be affected by several nutrition-derived compounds, such as by the commonly applied feed additive butyrate, possibly leading to feed-drug interactions. The aim of this study was to provide some evidence if butyrate can alter the activity of hepatic CYPs in chickens exposed to CYP-inducing xenobiotics, monitoring for the first time the possibility of such interaction. Ross 308 chickens in the grower phase were treated with daily intracoelomal phenobarbital (PB) injection (80 mg/kg BW), applied as a non-specific CYP-inducer, simultaneously with two different doses of intra-ingluvial sodium butyrate boluses (0.25 and 1.25 g/kg BW) for 5 days. Activity of CYP2H and CYP3A subfamilies was assessed by specific enzyme assays from isolated liver microsomes. According to our results, the lower dose of orally administered butyrate significantly attenuated the PB-triggered elevation of both hepatic CYP2H and CYP3A activities, which might be in association with the partly common signalling pathways of butyrate and CYP-inducing drugs, such as that of PB. Based on these data, butyrate may take part in pharmacoepigenetic interactions with simultaneously applied drugs or other CYP-inducing xenobiotics, with possible consequences for food safety and pharmacotherapy. Butyrate was found to be capable to maintain physiological CYP activity by attenuating CYP induction, underlining the safety of butyrate application in poultry nutrition.

Effects of oral butyrate application on insulin signaling in various tissues of chickens

The influence of butyrate on insulin signaling in chickens was studied because butyrate is produced during microbial fermentation in the large intestine of birds, and butyrate is widely used as a feed additive in animal production. Ross 308 broiler chickens received a daily intraingluvial bolus of sodium butyrate (0.25 g/kg body weight) on days 20-24 of life (n = 10). Plasma butyrate concentration increased after receiving oral butyrate treatment (P < 0.001). Oral butyrate application was associated with decreased protein expression of insulin receptor β subunit (IRβ) in liver (P = 0.008) and both abdominal (P = 0.003) and subcutaneous adipose tissue (P < 0.001), but with elevated IRβ expression in muscle (P = 0.045), assessed by Western blotting. The quantity of hepatic phosphatidyl-inositol-3-kinase was reduced in the butyrate-treated group (P = 0.007); further, mammalian target of rapamycin was downregulated by butyrate in liver (P < 0.001) and subcutaneous adipose tissue (P = 0.038). Oral butyrate application provoked reduced systemic insulin sensitivity in chickens, indicated by elevated fasting blood glucose and subsequently, insulin level. However, responses of insulin signaling cascade to butyrate were tissue specific, suggesting that butyrate could act on glucose shifting among tissues by selectively increasing the glucose uptake of skeletal muscle via IRβ upregulation.

Effects of Lactobacillus plantarum 2142 and sodium n-butyrate in lipopolysaccharide-triggered inflammation: comparison of a porcine intestinal epithelial cell line and primary hepatocyte monocultures with a porcine enterohepatic co-culture system

This study was based on our previously developed double-layered enterohepatic co-culture system, composed of nontumorigenic porcine intestinal epithelial cell line (IPEC-J2) and primary culture of porcine hepatocytes. The anti-inflammatory effect of spent culture supernatant of Lactobacillus plantarum 2142 (Lp2142; 13.3%) and sodium n-butyrate (2 mM) was tested on IPEC-J2 and hepatocyte monocultures as well as on the gut-liver co-culture. To mimic inflammation, lipopolysaccharide (LPS; 1 and 10 μg/mL) was applied. Production of IL-8 and IL-6 was measured as a marker of inflammatory responses. The paracellular permeability of the intestinal epithelium was also monitored by fluoresceinisothiocyanate-labeled dextran 4 assay. Significant increase of IL-8 concentration was observed in the IPEC-J2 monoculture (P < 0.01) while the level of IL-6 was not changed following LPS treatment. Concentration of IL-8 and IL-6 was grown significantly in hepatocyte monocultures (P < 0.05 and P < 0.001) as well as in the co-culture after 10 μg/mL LPS treatment (P < 0.001 and P < 0.001). One microgram per milliliter LPS caused elevated IL-8 level in the co-culture (P < 0.001) and in the hepatocyte monoculture (P < 0.01), while it caused increased IL-6 level only in the hepatocytes (P < 0.001). Production of IL-8 was significantly decreased by butyrate in case of 1 μg/mL as well as 10 μg/mL LPS exposure in the co-culture (P < 0.001). Application of butyrate also reduced IL-6 level in the co-culture after 10 μg/mL LPS treatment (P < 0.01). Lactobacillus plantarum 2142 decreased IL-8 level after incubation with 1 μg/mL LPS (P < 0.001), while in case of 10 μg/mL LPS treatment only a marginal lowering in IL-8 (P = 0.064) release was measured. The IL-6 concentration was significantly reduced (P < 0.01 in case of 1 μg/mL LPS treatment) by Lp2142 in the co-culture. Contrarily, the elevated IL-8 and IL-6 level of hepatocytes has not been reduced in case of either butyrate or Lp2142 addition. The enterohepatic co-culture model offers a possibility for fast and reliable screening of new candidates against enteric inflammation, which are of special interest in porcine medicine and health management. According to our results, Lp2142 and butyrate both seem to be effective as anti-inflammatory agents in LPS-triggered inflammatory response, tested in the gut-liver co-culture model.

Systemic inflammatory response syndrome (SIRS) induced by carbon tetrachloride in rats

We have observed the symptoms of systemic inflammatory response syndrome (SIRS) in male rats intoxicated by carbon tetrachloride (CCl(4)). Severe hypothermia, tachypnoea and increase in the heart beat min were diagnosed. These symptoms developed in the first hour of intoxication. The hepatic dysfunction was characterized by elevated bilirubin levels. In the sera we have measured increases in the activity of secretable (group II) phospholipase A(2) sPLA(2) (2,8x) and 6-ketoprostaglandin F(1alpha) (KPGF) (1,44x). Supposedly the free radicals derived from CCl(4)-mainly trichloromethyl-could induce the prompt reaction of SIRS and the release of sPLA(2) as well as the formation of KPGF. Our findings show that in the early phase of CCl(4) intoxication the symptoms of SIRS can be related to elevation of sPLA(2) and the products of cyclooxygenase II.

Genetic relatedness in wintering groups of house sparrows (Passer domesticus)

Social behaviour of group-living animals is often influenced by the relatedness of individuals, thus understanding the genetic structure of groups is important for the interpretation of costs and benefits of social interactions. In this study, we investigated genetic relatedness in feeding aggregations of free-living house sparrows (Passer domesticus) during the nonbreeding season. This species is a frequent model system for studies of social behaviour (e.g. aggression, social foraging), but we lack adequate information on the kin structure of sparrow flocks. During two winters, we ringed and observed sparrows at feeding stations, and used resightings to identify stable flock-members and to calculate association indices between birds. We genotyped the birds using seven highly polymorphic microsatellite loci, and estimated pairwise relatedness coefficients and relatedness categories (close kin vs. unrelated) by maximum likelihood method. We found that most birds were unrelated to each other in the flocks (mean +/- SE relatedness coefficient: 0.06 +/- 0.002), although most individuals had at least a few close relatives in their home flock (14.3 +/- 0.6% of flock-mates). Pairwise association between individuals was not significantly related to their genetic relatedness. Furthermore, there was no difference between within-flock vs. between-flock relatedness, and birds had similar proportions of close kin within and outside their home flock. Finally, relatedness among members of different flocks was unrelated to the distance between their flocks. Thus, sparrow flocks were not characterized by association of relatives, nevertheless the presence of some close kin may provide opportunity for kin-biased behaviours to evolve.

Bilateral striatal lesion associated with varicella

Bilateral striatal lesion is characterised by a specific clinical syndrome (encephalopathy with rigidity, irritability, variable pyramidal, and extrapyramidal symptoms, speech abnormalities) and symmetrical lesion of the basal ganglia including the caudate nucleus, the putamen, and occasionally other nuclei. We report three cases in whom bilateral striatal lesion developed in association with varicella. Each patient recovered completely and showed no signs of cognitive deficiency, chorea or hyperkinetic syndrome, all of which have been reported as sequelae of BSL associated with other conditions. These cases suggest that bilateral striatal lesion may be an immune-mediated complication of varicella.

Photocycle of dried acid purple form of bacteriorhodopsin

The photocycle of dried bacteriorhodopsin, pretreated in a 0.3 M HCl solution, was studied. Some properties of this dried sample resemble that of the acid purple suspension: the retinal conformation is mostly all-trans, 15-anti form, the spectrum of the sample is blue-shifted by 5 nm to 560 nm, and it has a truncated photocycle. After photoexcitation, a K-like red-shifted intermediate appears, which decays to the ground state through several intermediates with spectra between the K and the ground state. There are no other bacteriorhodopsin-like intermediates (L, M, N, O) present in the photocycle. The K to K' transition proceeds with an enthalpy decrease, whereas during all the following steps, the entropic energy of the system decreases. The electric response signal of the oriented sample has only negative components, which relaxes to zero. These suggest that the steps after intermediate K represent a relaxation process, during which the absorbed energy is dissipated and the protein returns to its original ground state. The initial charge separation on the retinal is followed by limited charge rearrangements in the protein, and later, all these relax. The decay times of the intermediates are strongly influenced by the humidity of the sample. Double-flash experiments proved that all the intermediates are directly driven back to the ground state. The study of the dried acid purple samples could help in understanding the fast primary processes of the protein function. It may also have importance in technical applications.

Characterization of the proton-transporting photocycle of pharaonis halorhodopsin

The photocycle of pharaonis halorhodopsin was investigated in the presence of 100 mM NaN(3) and 1 M Na(2)SO(4). Recent observations established that the replacement of the chloride ion with azide transforms the photocycle from a chloride-transporting one into a proton-transporting one. Kinetic analysis proves that the photocycle is very similar to that of bacteriorhodopsin. After K and L, intermediate M appears, which is missing from the chloride-transporting photocycle. In this intermediate the retinal Schiff base deprotonates. The rise of M in halorhodopsin is in the microsecond range, but occurs later than in bacteriorhodopsin, and its decay is more accentuated multiphasic. Intermediate N cannot be detected, but a large amount of O accumulates. The multiphasic character of the last step of the photocycle could be explained by the existence of a HR' state, as in the chloride photocycle. Upon replacement of chloride ion with azide, the fast electric signal changes its sign from positive to negative, and becomes similar to that detected in bacteriorhodopsin. The photocycle is enthalpy-driven, as is the chloride photocycle of halorhodopsin. These observations suggest that, while the basic charge translocation steps become identical to those in bacteriorhodopsin, the storage and utilization of energy during the photocycle remains unchanged by exchanging chloride with azide.

Intermediate spectra and photocycle kinetics of the Asp96 --> asn mutant bacteriorhodopsin determined by singular value decomposition with self-modeling

Singular value decomposition with self-modeling is applied to resolve the intermediate spectra and kinetics of the Asp96 --> Asn mutant bacteriorhodopsin. The search for the difference spectra of the intermediates is performed in eigenvector space on the stoichiometric plane. The analysis of data at pH values ranging from 4 to 8 and temperatures between 5 and 25 degrees C reveals significant, early partial recovery of the initial state after photoexcitation. The derived spectra are not biased by assumed photocycles. The intermediate spectra derived in the initial step differ from spectra determined in prior analyses, which results in intermediate concentrations with improved stoichiometric properties. Increasingly more accurate photocycles follow with increasing assumed complexity, of which parallel models are favored, consistent with recent, independent experimental evidence.

Singular value decomposition with self-modeling applied to determine bacteriorhodopsin intermediate spectra: analysis of simulated data

An a priori model-independent method for the determination of accurate spectra of photocycle intermediates is developed. The method, singular value decomposition with self-modeling (SVD-SM), is tested on simulated difference spectra designed to mimic the photocycle of the Asp-96 --> Asn mutant of bacteriorhodopsin. Stoichiometric constraints, valid until the onset of the recovery of bleached bacteriorhodopsin at the end of the photocycle, guide the self-modeling procedure. The difference spectra of the intermediates are determined in eigenvector space by confining the search for their coordinates to a stoichiometric plane. In the absence of random noise, SVD-SM recovers the intermediate spectra and their time evolution nearly exactly. The recovery of input spectra and kinetics is excellent although somewhat less exact when realistic random noise is included in the input spectra. The difference between recovered and input kinetics is now visually discernible, but the same reaction scheme with nearly identical rate constants to those assumed in the simulation fits the output kinetics well. SVD-SM relegates the selection of a photocycle model to the late stage of the analysis. It thus avoids derivation of erroneous model-specific spectra that result from global model-fitting approaches that assume a model at the outset.

Interpretation of the spatial charge displacements in bacteriorhodopsin in terms of structural changes during the photocycle

We have recently introduced a method, made possible by an improved orienting technique using a combination of electric and magnetic fields, that allows the three-dimensional detection of the intramolecular charge displacements during the photocycle of bacteriorhodopsin. This method generates electric asymmetry, a prerequisite for the detection of electric signal on the macroscopic sample, in all three spatial dimensions. Purple membrane fragments containing bacteriorhodopsin were oriented so that their permanent electric dipole moment vectors were perpendicular to the membrane plane and pointed in the same direction. The resulting cylindrical symmetry was broken by photoselection, i. e., by flash excitation with low intensity linearly polarized light. From the measured electric signals, the three-dimensional motion of the electric charge center in the bacteriorhodopsin molecules was calculated for the first 400 microseconds. Simultaneous absorption kinetic recording provided the time-dependent concentrations of the intermediates. Combining the two sets of data, we determined the discrete dipole moments of intermediates up to M. When compared with the results of current molecular dynamics calculations, the data provided a decisive experimental test for selecting the optimal theoretical model for the proton transport and should eventually lead to a full description of the mechanism of the bacteriorhodopsin proton pump.

Cellular basis of biventricular hypertrophy and arrhythmogenesis in dogs with chronic complete atrioventricular block and acquired torsade de pointes

BACKGROUND

In the dog with chronic complete atrioventricular block (AVB), torsade de pointes arrhythmias (TdP) can be induced reproducibly by class III antiarrhythmic agents. In vivo studies reveal important electrophysiological alterations of the heart at 5 weeks of AVB, resulting in increased proarrhythmia. Autopsy studies indicate the presence of biventricular hypertrophy. In this study, the cellular basis of proarrhythmia and hypertrophy in chronic AVB was investigated.

METHODS AND RESULTS

From chronic-AVB dogs with increased heart weights and TdP, left midmyocardial and right ventricular myocytes were isolated by enzymatic dispersion. These myocytes were significantly larger than sinus rhythm (SR) controls. In chronic AVB, the action potential spike-and-dome configuration was preserved. However, the action potential duration (APD) at 95% and 50% of repolarization of the left midmyocardium was significantly larger in chronic AVB than in SR, with little change in the right ventricle, causing enhanced interventricular dispersion of repolarization at slow pacing rates. Treatment with the class III agent almokalant increased the APD to a much larger extent in chronic-AVB than in SR myocytes and resulted in a higher incidence of early afterdepolarizations (EADs). EADs had their takeoff potential between -35 and 0 mV. There was no evidence that spontaneous sarcoplasmic reticulum Ca2+ release underlies these EADs.

CONCLUSIONS

In the dog, chronic AVB leads to hypertrophy of both right and left ventricular myocytes. The repolarization abnormalities predisposing for class III-dependent TdP in vivo are the results of cellular electrophysiological remodeling.

Studies on the effect of ursodesoxycholic acid on rats with acute carbontetrachloride injury

Bilirubin is a sensitive marker of toxic liver injury. Carbontetrachloride (CCl4) is used in some manufactures and laboratories. An acute intoxication is a peril. We have performed experiments to state total, indirect and direct bilirubin levels in rats exposed to a single CCl4 dose of 1.25 ml/kg. Total bilirubin in normal rats is 3.13 +/- 0.13 mumol/l. 58.6% is direct conjugated and 41.3% indirect unconjugated bilirubin. One hour after CCl4 administration bilirubin started to increase and reached its peak in the second hour. 24 h later a decrease began but even 72 h after intoxication it was not normalized. Ursodesoxycholic acid (UDCA, CAS 128-13-2, Ursofalk) treatment (25 mg/kg/dose) lowered bilirubin, returning to normal level 24 h after CCl4 administration. Hypothermia aggravates intoxications. In CCl4 lesion it develops 1 h after exposure. UDCA has not influenced low body temperature but liver function, conjugating capacity was restored. In CCl4 poisoning it is suggested to start UDCA treatment as early as possible and to continue it for some more days after improvement of serum bilirubin concentration.

[Changes in fat metabolism in acute carbon tetrachloride intoxication of rats]

CCl4 is an organic solvent and a well known hepatotoxic agent. Injury is mediated by reactive free radicals, mainly-CCl3 (trichloromethyl). Liver lesion develops within one-two hours, however, late toxic effects may appear after a delay of several hours or two to three days. Some drugs and liver toxicants cause disturbances in synthesis and metabolism of triglycerides, cholesterol and lipoproteins, thus damaging the basic resource for living cells. In our experiments a single 1.25 ml/kg CCl4 dose was administered s.c. to male Wistar rats. 24 hours later triglyceride level increased in the plasma by 223%. Cholesterol content suffered no changes. HDL-C level decreased by 40%. LDL-C concentration was higher by 235%. Cholesterol/HDL-C ratio increased by 0.75% on account of the practically unchanged cholesterol amount in the blood. The most often used calculation (Friedewald equation) LDL-C/HDL-C ratio was higher by 305%. The increased triglyceride content in the blood is in correlation with the fatty degeneration of the liver. The high LDL-C/HDL-C ratio may point to incipient atherosclerotic complications. The pathological lipid levels measured 24 hours after intoxication claim for delayed toxic effects to be taken into consideration. It may be suggested to determine the main lipid parameters after carbon tetrachloride exposition.

[Experimental myocardial infarct in rats induced by ligation of the coronary vessels. Electrophysiologic and ultrastructural study]

Ischemic damage of rat myocardium was produced by ligature of coronary arteries. Animals were studied in three groups: those dying of dysrhythmia, animals after ischemia lasting 10 minutes and 20 minutes. All of them were investigated by ECG and extrasystoles, bigeminia, trigeminia, salvos, ventricular tachycardia and fibrillation were found. Groups with ECG finding were sampled for electron microscopy. Ultrastructural findings documented ischemic damage of cardiomyocytes-clearing of basal sarcoplasm, clearing of perinuclear zones, occurring of cytolytic regions and even necrotic disintegration of cardiocytes.

Metabolic actions of a single atenolol and metoprolol dose

Atenolol (CAS 29122-68-7) and metoprolol (CAS 37350-58-6) are beta 1-selective adrenoceptor antagonists without intrinsic sympathomimetic activity. beta-Receptor blockers influence carbohydrate- and lipid metabolism. Liver is a central organ of these processes. The metabolic fate of a single oral atenolol and metoprolol dose and their actions on carbohydrate- and lipid parameters have been investigated. Healthy male rats received a dose reducing heart beat/min by 25% (atenolol: 6 mg/kg; metoprolol: 10 mg/kg). About 9% of atenolol is metabolized by cytochrome P-450 (P-450). P-450-dependent functions (aminopyrine-N-demethylase, hexobarbital biotransformation time) were not inhibited. Serum bilirubin was normal. Triglyceride (TG), total cholesterol and HDL-cholesterol levels of the plasma were not affected. Transient blood glucose increase was measured returning to initial value at 120 min. Metoprolol is metabolized by hepatic monooxygenases. P-450-dependent functions were inhibited correlating to the lowered P-450-content of the microsomes. High TG level and decreased HDL-cholesterol content were measured. Blood glucose was significantly high. The liposoluble metroprolol affected the hepatic functions more than the hydrophilic atenolol. The monitoring of blood glucose during beta-receptor antagonist treatment may be suggested.

[Preparation and pharmacologic profile of derivatives of alkoxyphenylcarbamic acid with potential effects on the cardiovascular system]

In a systematic study of the relationship between the chemical structure and beta-adrenolytic activity, eleven derivatives of the 4-alkoxysubstituted phenylcarbamic acids were prepared. The beta-adrenolytic efficiency of the compounds was studied in the isolated spontaneously beating guinea-pig atria and expressed as pA2 values against isoprenaline tachycardia. Negative chronotropic and antidysrhythmic activity were also evaluated. All of the compounds studied were local anesthetically active and their indexes of efficiency were 3-50 fold higher in comparison with standards cocaine and procaine. The acute toxicity of the compounds was within the acceptable limits.

Metoprolol and propranolol treatment in carbon tetrachloride-induced hepatic injury

The effects of beta 1-selective metoprolol (CAS 37350-58-6) and the nonselective beta-adrenoceptor antagonist propranolol (CAS 525-66-6) were investigated in healthy and CCl4 damaged male rats. Treatments were performed for 16 days, orally with dosages reducing heart beat/min by 25% (metoprolol 10 mg/kg, propranolol 1 mg/kg). Liver glycogen content was not influenced by either beta-blocker in healthy animals. CCl4-induced loss of glycogen was equally moderated by metoprolol and propranolol. Blood glucose increased in metoprolol treated healthy and liver damaged rats after a single dosage likewise following prolonged treatment. Propranolol was without effect on blood glucose level. Cytochrome P-450 decline in microsomal fraction was greater in metoprolol, than in propranolol treated healthy animals. However, the severe fall elicited by liver injury was moderated by metoprolol and normalised by propranolol. Cytochrome b5 seems to be involved in metoprolol metabolism. Cytochrome P-450-dependent aminopyrine-N-demethylase was impeded by metoprolol in animals with healthy liver. The serious inhibition caused by CCl4 was moderated by metoprolol and with a better result by propranolol. The high serum bilirubin level in liver lesion was lowered by metoprolol and particularly by propranolol. Neither phase I metabolic process aminopyrine-N-demethylation nor phase II glucuronidation were normalised. A comparison of this data with the results of a previous 12-day treatment schedule indicates that no changes in efficacy occurred with longer treatment. The present results pertain to the importance of the selection of beta-adrenoceptor blocker in liver lesion.(ABSTRACT TRUNCATED AT 250 WORDS)

The effect of subacute prazosin treatment on hepatic metabolic enzyme system of young and elderly rats

We have studied cytochrome P-450 content, aminopyrine-N-demethylating activity, serum bilirubin level, in young 10 weeks old and elderly, 14 months old CFY rats grouped according to sex. The effect of the selective alpha 1-adrenoceptor antagonist antihypertensive prazosin was examined in the previously described groups of animals. We could state that neither oxidative nor conjugative reactions of the liver declined with aging. In a subacute 12 days treatment period prazosin has not impaired liver functions.

Effects of tamoxifen and levonorgestrel treatment on carbon tetrachloride induced alterations in rats

Oestrogens cause progression in liver lesion, and thus ovariectomy improves hepatic injury both functionally and histologically. In the present study the efficacy of the antioestrogen tamoxifen (CAS 10540-29-1) was examined in chronical carbon tetrachloride damage. The results were compared with the effect of the progestogen levonorgestrel. Male Wistar rats were treated for 16 days. Blood sampling and autopsy were performed 2 h after last tamoxifen resp. levonorgestrel and 1 h after last CCl4 dosage. Tamoxifen diminished water content of the healthy liver. By fairly the same ratio it decreased high water content of the damaged liver. Levonorgestrel moderated water imbibition in CCl4 impairment. Tamoxifen caused protein synthesis in healthy and in injured liver. Levonorgestrel could not prevent protein loss associated with CCl4 damage. Tamoxifen counteracted, levonorgestrel moderated glycogen loss in liver lesion. Blood glucose was normal in all examined groups. Cytochrome P-450 decrease in CCl4 injury was moderated but not normalised by tamoxifen. Levonorgestrel was less effective. Cytochrome b5 content diminished in CCl4 lesion and both treatments restored it. Aminopyrine-N-demethylase was impaired by liver injury. An improvement was measured correlating with microsomal cytochrome P-450 content. This was significant with tamoxifen but not following levonorgestrel administration. The pathological serum bilirubin level of CCl4 lesion was normalised by tamoxifen as well as levonorgestrel treatment. The progestogen levonorgestrel moderated liver injury in reducing high water content, glycogen loss and normalising serum bilirubin. The antioestrogen tamoxifen seems to be a promising treatment in chronic hepatic impairment.(ABSTRACT TRUNCATED AT 250 WORDS)

Correlations between hepatic monooxygenase system and glycogen storage

In experiments performed on female Wistar rats we have stated that simultaneously with glycogen mobilisation occurring immediately after epinephrine injection the amount of cytochrome P-450 (cP-450) was reduced. A characteristic cP-450 dependent function hexobarbital biotransformation was inhibited. No changes in hepatic protein and water content and serum bilirubin were measured. Glycogen and cP-450 loss and functional impairment depend on the administered epinephrine dose and time of treatment. We have proven that reduced activity of mixed function monooxygenase is related only to diminished glycogen content of the liver. Restitution of glycogen stores as well as amount and function of cP-450 were parallel.

Alpha-adrenergic receptors in the regulation of liver functions

Rat liver contains 80% alpha 1 and 20% alpha 2 receptors. The role of adrenergic regulation of liver functions was studied by administration of antagonist and agonist pharmaca. Female rats were treated with the selective alpha 1 receptor blocker prazosin. A transitory inhibition of microsomal monooxygenases was observed after 5 days which was terminated at the 12 day. A 18.7% loss of glycogen was measured at this time indicating a slight adrenergic glycogenolytic effect. Dihyd 50-ergocryptime an equal lebocker of alpha 1 alpha 2 receptori preserved glycogen content and has not impaired liver functions. Agonist epinephrine inhibited monooxygenase functions and mobilised 75% of hepatic glycogen. Simultaneous administration of prazosin with epinephrine resulted into glycogen loss due to alpha 2 receptor stimulation. Dihydroergocryptine antagonised rather the metabolic actions of epinephrine. We have established that alpha 2 receptors are also involved in hepatic carbohydrate metabolism.

Different mechanisms in the hepatic actions of estrogens

Literary data proved evidence that uterine actions of estrogens develop through different receptor systems. We performed experiments to examine whether different mechanisms are also involved in the hepatic effects of estrogenic steroids. Female rats were treated with a single dose of 5 mg/kg estrone. Dry liver weight and protein content increased. Both responses were blocked by prior administration of natural antiestrogen progesterone. Increased wet organ weight and water content were measured as edematous reactions. They can be attributed to the depolymerisation of mucopolysaccharides. Progesterone could not prevent these effects. Estrone induced glycogen synthesis in the liver. This was counteracted by progesterone treatment. To elucidate the possible role of the adenylcyclase system the animals were treated with beta-receptor blocker propranolol which had no effect either on liver glycogen content or on estrone induced synthesis. Dihydroergocryptine, an equal blocker of alpha 1- and alpha 2-receptors, did not interfere with glycogenetic action of estrone either. The selective alpha 1-receptor blocker prazosin decreased the liver glycogen content and inhibited glycogenetic response to estrone. Our results proved that estrogens display their hepatic effects by several mechanisms that can be selectively blocked or moderated.

Hepatic actions of progestogenic steroids

The effects of two oral progestogens, norethisterone and d-norgestrel, were studied on hepatic functions in CFY female rats. In healthy animals both progestogens inhibited cytochrome-P-450 dependent nonspecific mixed function monooxygenases. Serum bilirubin and cholylglycin RIA values were normal. Protein and glycogen content of the liver remained intact after norethisterone, d-norgestrel reduced glycogen. The pathologic values characteristic for chronic carbon-tetrachloride damage improved on a highly significant grade when these progestogens were simultaneously administered. The progestogens inhibited mixed function monooxygenases. We may presume that in this way they inhibited the formation of hepatotoxic trichloromethyl free radical and improved several liver functions.

Estrogens as disposing factors in experimental liver injury

The activity of hexobarbital metabolising enzymes of the liver is decreased as a consequence of both acute and chronical carbon tetrachloride damage. Simultaneous administration of estrogens was followed by more severe morphological and functional impairment although estrogens are not burdening the healthy liver. The beta receptor blocking propranolol prevented functional lesion, moderated fatty degeneration and liver cell necrosis in chronic carbon tetrachloride injury. A simultaneous estrogen administration decreased the therapeutic efficacy of beta blockade, however functional and morphological protective effects were not completely abolished. Estrogen medication should be rather avoided in hepatic damage.

[Diabetes mellitus and Addison's disease)]

The authors diagnosed diabetes mellitus together with Addison's disease in a 38 year-old male patient. They are discussing therapeutic difficulties arising from the biglandular hypofunctional condition and the problems of the pathogenesis.

The role of sex differences in the effect of anabolics on the liver

The effect of two anabolic steroids, norandrostenolone-phenylpropionate (Nerobolil) and norandrostenolone-decanoate (Retabolil) on the liver was studied in rats. Body weight, wet liver weight and the protein content of the liver homogenisates were found to increase under the effect of anabolic treatment, the most explicitely in females treated with Nerobolil. The function of the liver to metabolize hexobarbital, measured in vivo, is increased by a single dose of anabolic. The prolongation of treatment keeps on shortening hexobarbital anaesthesia only in females. Even 8 weeks after the end of treatment the effect is invariably lasting in females, in males it is not. Studies of the vaginal cycle cannot prove a decline of ovarial function. In females the hepatotropic effect of anabolic treatment, performed simultaneously with the chronic carbon tetrachloride lesion can be demonstrated. The liver weight and protein content are maintained on the control level. Under the effect of anabolic treatment the function to metabolize the effect of anabolic treatment the function to metabolize hexobarbital, which has been impaired by the lesion, remains near the level of the untreated animals. Our experiments support the observations of the inductive property of the steroids being parallel to their anabolic characteristics. Their catatoxic effect is pronounced in females. Nerobolil was found to be more advantageous from the point of view of both anabolic and hepatotropic effect. Our experiments do not suggest the possibility of liver damage during the administration of these two anabolics. The effect of the anabolics on the enzymatic induction may be of therapeutic value when adequate preparations are selected and sex differences as well as the character of the liver damage are taken into consideration.