Total Liver Protein Research Articles

Evaluation of silymarin and / or ginger effect on induced hepatotoxicity by carbon tetrachloride in male albino rats

Liver disease appears to be increase. Part of this increase may be due to our frequent contact with chemicals and other environmental pollutants. The amount of medicne consumed has increased greatly which could be danger to the liver. The hepatoprotective flavonoid, silymarin (7.56 mg/Kg b. wt.) and ginger (Zingiber officinale) (1% of diet) for 4 weeks were used to ameliorate the liver injury in rats intoxicated with carbon tetrachloride (CCL4 , single acute dose 4 ml/ Kg b. wt. of 50% v/v CCL4 in olive oil, subcutaneous). The obtained results showed that CCL4 decreased serum and liver total protein and albumin. Also reduced glutathione content. The antioxidant enzymes; glutathione-S-transferase, superoxide dismutase and catalase activity decreased in the liver of CCL4 toxicity group. On the other hand, CCL4 toxicity increased serum and liver bilirubin, total lipid and total cholestertol levels. In addition, liver function (aspartate aminotransferase, alanine aminotransferase and alkaline phosphatase) and liver lipid peroxidation content showed significant increase in the CCL4 treated group. Previous parameters turned back to normal values in carbon tetrachloride intoxicated rats after treating with silymarin and/ or ginger for one month. Meanwhile, the most interesting effect was induced by a combination of silymarin and ginger. Hence, the present findings will provide a potential scope for future use of ginger for the treatment of liver disorders.

Antitumor activities of iodoacetate and dimethylsulphoxide against solid Ehrlich carcinoma growth in mice.

Treatment of tumor-bearing mice with LD12.5 values of iodoacetate; IAA (1.84 mg/100 g b.w.) and/or dimethylsulphoxide; DMSO (350 mg/100 g b.w.) significantly increased the cumulative mean survival time and percentage of survivors and reduced the mean tumor weight, compared to tumor-bearing controls, however, a more pronounced effect is recorded in the combined treatment. Also, an increase in the life span (ILS%) and tumor growth inhibition ratio (T/C%) are reported and amounted to 145.78 and 43.80%, 195.54 and 61.30% and 220.77 and 78.40% in IAA, DMSO and combined-treated groups, respectively. Results obtained from biochemical studies reveal that a single IAA treatment of tumor-bearing mice significantly increased the levels of plasma lactate dehydrogenase (LDH) activity, while it also significantly decreased the levels of plasma glucose and liver total protein, RNA and DNA, compared to normal controls. On the other hand, a single DMSO treatment significantly elevated the activities of blood antioxidant enzymes, i.e. glutathione peroxidase (GPx) and glucose-6-phosphate dehydrogenase (G6PDH) and decreased the liver RNA and DNA levels. Combined treatment increased significantly the levels of plasma LDH and erythrocytes G6PDH activities, as well as liver glycogen, and in contrast it decreased the levels of liver total protein, RNA and DNA, compared to normal controls.

Proteomic analysis of the rat liver

Rat is a useful, widely used animal model for biological and toxicity studies. We analyzed total and cytosolic rat liver proteins by applying proteomics technologies. The proteins were separated by two-dimensional electrophoresis employing broad and narrow range immobilized pH gradient strips, followed by MALDI-MS analysis of the tryptic digests. Two hundred and seventy-three different gene products were identified, of which approximately 60% were enzymes with a broad spectrum of catalytic activities. Most of the identified proteins were detected in other rat protein samples as well, which were analyzed in our laboratory. Fifteen gene products were detected for the first time. These were represented by one spot each, whereas most of the frequently detected proteins were represented by multiple spots. In average, approximately five to 10 spots corresponded to one gene product. The database includes a large number of proteins known to be involved in toxicology-relevant pathways and may be useful in toxicity prediction studies.

Eicosapentaenoic acid supplementation reduces tumor volume and attenuates cachexia in a rat model of progressive non-metastasizing malignancy.

Eicosapentaenoic acid (EPA) has been shown to have anti-inflammatory and tumor growth inhibitory effects clinically and experimentally; evidence also supports the role of EPA in attenuating cancer-associated weight loss, but the mechanisms of these effects remain to be defined. As the liver plays a central role in modulating nutritional status and the cachexia syndrome, we examined the liver and nutritional parameters indicative of cachexia along with the tumor volume in response to oral EPA supplementation in a rat model of progressive non-metastasizing malignancy. Fischer 344 rats implanted with the methylcholanthrene-induced fibrosarcoma (MCA) were trained to meal-feed with access to food from 8:00 PM to 8:00 AM and water ad libitum. On day 13, rats were randomly divided into 3 study groups: (1) 5.0 g/kg per day EPA plus 10 IU vitamin E/g fat, (2) 5.0 g/kg per day corn oil plus 10 IU vitamin E/g fat, and (3) 5.0 g/kg per day saline plus 10 IU vitamin E/g saline. The treatment was delivered via oral gavage twice daily. The animals were killed on day 29, and serum plus tissues (ie, liver and lung) were collected and frozen for analysis. Parameters evaluated include the following: tumor volume, weight loss, liver weight, total liver protein, liver lipid content, serum albumin content, and macrophage inflammatory protein-2 (MIP-2) levels. EPA-treated rats showed a reduction in tumor volume compared with corn oil (25% reduction, p < .01) and saline (33% reduction, p < .01) animals. EPA rats also demonstrated increased liver weight (p < .01) and total liver protein levels (p < .03) over saline-treated animals. EPA- and corn oil-treated rats received more calories than the saline group because of the dietary fat treatments (p < .01) and had elevated lipid content in their livers (p = .05 and p = .04, respectively) compared with saline rats. Serum albumin (a marker of liver function) and MIP-2 levels (a marker of the hepatic acute phase response) were not different between treatment groups. EPA supplementation resulted in a dramatic reduction of tumor volume and mild improvements in weight maintenance. In addition, EPA-treated animals demonstrated increased total liver protein and serum protein levels. Regression analyses showed that the weight and protein differences between treatment groups were not correlated with individual tumor volumes. The increase in liver and serum protein was not explained by differences in albumin or MIP-2. We conclude that the tumor growth inhibitory effects and anticachexiogenic effects of EPA are independent phenomena, and the effects on cachexia may be related to increased levels of undefined protein(s) in the liver and serum. To our knowledge, this is the first study to demonstrate the effects of EPA in the MCA fibrosarcoma model and is also novel in its evaluation of EPA as an anticachexiogenic therapy in progressive non-metastasizing malignancy. Further studies may identify the protein(s) elevated in the liver and the mechanisms for the development of EPA nutritional therapies for the treatment of progressive malignancies.

Age-related changes in microsome-dependent conversion of T-T, thyroid function and cadmium toxicity in albino rat.

The impact of age on microsomal function, manifested by its ability to convert thyroid hormone thyroxine (T ) to triiodothyronine (T&), was investigated using four age     '& ( )  -months). The data show impaired microsomal function with advancing age represented by a significant decrease in serum levels of T& and T&/T ratio. There was a decline in the liver glutathione (GSH), total proteins and serum aspartate aminotransferase (AST), alanine aminotransferase (ALT) and gamma- glutamyl transpeptidase (*GT). There was an-age associated increase in liver content of the lipid peroxidation products, thiobarituric acid (TBA)-reactants and the serum total protein.
  ++ ,   - .     '(+ - /  ' + -old)  +0- 1-) mg/kg CdCl 2their controls were injected with distilled water. A higher susceptibility of senile rats to cadmium toxicity was manifested as a significantly higher decrease in their serum T& level and T&/T ratio than adult compared to control. A reduction in the adaptive response of senile animals was manifested by a less increase in hepatic GSH in senile than adult as compared to control. The level of hepatic TBA-reactants was significantly higher in treated than in control group. The increase was more pronounced in the senile group. A marked hepatic cellular damage indicated by an increase in the serum levels of the AST and ALT was more pronounced in senile compared with adult rats. Treatment resulted in a decrease in the serum *GT and liver triglycerides (TG). The decrease in both parameters was more evident in senile as compared to adult group.

Melatonin reduces oxidative damage and increases survival of mice infected with Schistosoma mansoni

The tropical parasite Schistosoma mansoni causes granulomatous inflammation after its eggs lodge in hepatic portal capillaries. In vitro studies indicate that the host’s response involves the production of reactive oxygen species, although whether this occurs in vivo at the site of the infection is unknown. The role of oxidative processes in mice infected with S. mansoni was investigated in the current study using the antioxidant melatonin. In Experiment 1, the survival rate of infected mice with and without daily melatonin (10 mg/kg) administration was determined. After 56 d, 25 of 25 infected mice that were diluent treated had died. In contrast, 22 or 25 infected mice (88%) given melatonin were still alive at 56 d. Of these 22 surviving mice, melatonin injections were continued in 11 while the 11 others were switched to diluent. Within 10 d, 11 of 11 diluent-injected mice that were infected with S. mansoni were dead while 6 of 11 melatonin-treated mice survived. In Experiment 2, S. mansoni-infected mice were treated for 30 d with either melatonin or diluent. Uninfected, untreated mice served as controls. In these mice, the levels of lipid peroxidation (LPO) products, vitamin E, nitric oxide (NO), glutathione (GSH), and superoxide dismutase (SOD) activity in the liver, kidney, and spleen were measured. In the serum, cholesterol levels and liver damage (alkaline phosphatase (ALP), aspartate transaminases (AST), total protein, and albumin) were monitored. In addition, peroxynitrite anion (ONOO −) in the liver and kidney and inducible nitric oxide synthase (iNOS) in the spleen were immunocytochemically localized. Also, histopathological changes in the liver, kidney, and spleen were examined. The results documented increased LPO and NO levels and decreased vitamin E, GSH, and SOD activity in the liver, kidney, and spleen of S. mansoni-infected mice. Also, there was an increase in serum cholesterol and evidence of liver damage in the infected mice. Immunohistochemical results indicated positive staining of ONOO − in the liver and kidney and positive iNOS staining in the spleen of S. mansoni-infected mice. Histopathological observations revealed granuloma formation in the liver with eosinophil infiltration, a large number of megakaryocytes in the spleen, and degeneration with necrotic cells in some tubules of the kidney cortex in the infected mice. Melatonin administration after S. mansoni infection prevented most of the previously described changes. These results suggest that oxidative processes occur at the site of inflammation and are involved in the damaging effects of schistosomiasis and indicate that free radicals may be a major component of the disease. Likewise, melatonin, presumably due to its antioxidant and free radical scavenging activity, is highly protective against the pathological changes associated with schistosomiasis.

Determination of maximum permissible concentrations of industrial toxicants using the integral biochemical index

Effects of patented mixtures of substances, used as drilling fluids in petroleum industry, on the activity of enzymes (cathepsin D, EC 3.4.23.5; catalase, EC 1.11.1.6; and DNase, EC 3.1.4.6) and the content of analytes (malondialdehyde, fatty acids, free and collagen-associated hydroxyproline, bile acids, and total protein) in liver, gills, muscles, gonads, and bile have been studied under aquarium conditions in mature river flounder and one-year-old salmon for the purpose of determining maximum permissible concentrations. Measuring 25-30 independent biochemical parameters per organ is sufficient for establishing a direct relationship between the concentration of an industrial toxicant and the integral biochemical index, a new characteristic defined as the ratio of the number of biochemical parameters significantly deviating from control values to the total number of the parameters measured.

Plasminogen Deficiency Leads to Impaired Lobular Reorganization and Matrix Accumulation after Chronic Liver Injury

To determine the regulatory role of plasminogen in hepatic repair following a chronic liver injury, we injected carbon tetrachloride (CCl(4)) biweekly into mice lacking plasminogen (Plg(0)) and plasminogen-sufficient littermates (Plg(+)). On gross examination, we found that Plg(0) livers became enlarged and pale with foci of red nodules as early as 4 weeks after CCl(4) injection, while Plg(+) livers appeared minimally affected by 6 weeks. Microscopically, Plg(0) livers had a pronounced pericentral linking, with accumulation of centrilobular eosinophilic material in injured areas, which resulted in a significant increase in liver mass and total protein. Immunohistochemistry revealed that fibrin accumulated progressively in injured regions. However, the combined genetic loss of plasminogen and fibrinogen did not correct the abnormal phenotype. Mason's trichrome staining revealed intense signal in centrilobular regions and electron microscopy showed a marked increase in fibrillary material demonstrating an excessive accumulation of extracellular matrix in Plg(0) mice. The zone-specific increase in matrix components was associated with an increase in the number of activated hepatic stellate cells within injured sites of Plg(0) livers. Taken together, these data suggest that the progressive accumulation of fibrin-unrelated matrix substrates in Plg(0) livers after a chronic injury results from the combined effects of impaired proteolysis and increased matrix production.

Hypercholesterolemia, coronary artery disease and treatment in croatia

Palm oil is thermally oxidized to increase its palatability and this has been a usual practice in most homes. This study sought to assess the biochemical responses of rats to thermally oxidized palm oil diets. Therefore, Wistar strain albino rats (Rattus norveigicus) were fed with fresh palm oil (control) and thermally oxidized palm oil (test groups) diets and water ad libitum for 30 days. Then, the malondialdehyde (MDA) contents and total protein of the plasma and liver were determined. Subsequently, the plasma liver function markers [alanine transaminase (ALT), aspartate transaminase (AST), alkaline phosphatase (ALP), albumin (ALB) and total bilirubin (TBIL) ] and the lipid profile [triglyceride (TRIG), total cholesterol (T-CHOL), high density lipoprotein (HDL-CHOL) and low density lipoprotein (LDL-CHOL) ] were assayed. The results of the study revealed that there was a significant decrease (P < 0.05) in the plasma and liver total protein, ALB, TRIG and HDL-CHOL of the test groups when compared with the control. Conversely, there was a significant increase (P < 0.05) in the activities of ALT, AST and ALP, TBIL, T-CHOL, LDL-CHOL and plasma/liver MDA of the test groups when compared with the control. These effects were most pronounced in rats fed with 20 min-thermally oxidized palm oil diet. Hence, consumption of thermally oxidized palm oil diets had deleterious effects on biochemical indices in rats. Therefore, cooking with and/or consumption of palm oil subjected to heat treatment for several long periods of time should be discouraged in our homes as this might have deleterious effects on human health.

Effect of glutathione (GSH) depletion on the serum levels of triiodothyronine (T3), thyroxine (T4), and T3/T4 ratio in allyl alcohol-treated male rats and possible protection with zinc.

The current study is an attempt to elucidate the link between glutathione (GSH) as a major endogenous antioxidant and the thyroid hormone levels. Rats were treated with a single intraperitoneal (IP) dose of either ZnCl2 (5 mg/kg) or allyl alcohol (AIAI) (1.5 mmol/kg), which acts as a GSH-depleting agent. ZnCl2 and AIAI were administered either alone (Zn- and AlAl-treated groups) or in combination (AIAI + Zn-treated group). Blood and liver samples were collected 5 hours post treatment in all groups. Zinc was used because of its potential intracellular regulatory effect as a calcium antagonist. The data indicate a decrease in the serum levels of triiodothyronine (T3) and thyroxin (T4), the T3/T4 ratio, and serum and liver total protein in AlAl-treated rats. Increases in the serum levels of aminotransferases, hepatic calcium, and lipid peroxidation products were observed. The decrease in T3 and the T3/T4 ratio indicates a reduced capacity of the microsomes to convert T4 into T3. Rats treated with AlAl + Zn had replenished hepatic GSH and showed a marked decrease in the serum levels of aminotransferases and in the liver calcium contents and lipid peroxidation products compared to AlAl-treated rats. In contrast, zinc treatment failed to normalize the serum levels of total protein, T3 and T4, and the T3/T4 ratio in the same rats. Rat treated with ZnCI2 alone tended to have a lower serum protein level that was accompanied with a significant decrease in both serum T3 and the T3/T4 ratio. The effect of zinc in increasing capillary permeability with the probable leakage of some serum proteins including the thyroid-binding proteins could possibly be the reason behind this finding. Possible covalent binding of AIAI metabolites to some cellular proteins may explain the persistence of reduced liver protein levels in zinc-protected rats.

Synthesis rate of plasma albumin is a good indicator of liver albumin synthesis in sepsis.

Plasma albumin is well known to decrease in response to inflammation. The rate of albumin synthesis from both liver and plasma was measured in vivo by use of a large dose of L-[(2)H(3)-(14)C]valine in rats injected intravenously with live Escherichia coli and in pair-fed control rats during the acute-phase period (2 days postinfection). The plasma albumin concentration was reduced by 50% in infected rats compared with pair-fed animals. Infection induced a fall in both liver albumin mRNA levels and albumin synthesis relative to total liver protein synthesis. However, absolute liver albumin synthesis rate (ASR) was not affected by infection. In plasma, albumin fractional synthesis rate was increased by 50% in infected animals compared with pair-fed animals. The albumin ASR estimated in the plasma was similar in the two groups. These results suggest that hypoalbuminemia is not due to reduced albumin synthesis during sepsis. Moreover, liver and plasma albumin ASR were similar. Therefore, albumin synthesis measured in the plasma is a good indicator of liver albumin synthesis.

Effect of Dietary Barley β-Glucan on Cholesterol and Lipoprotein Fractions in Rat

The flours of three barley cultivars, namely Dolma (hull-less), DL-88 (hull-less) and BH-331 (hulled), containing 6·23, 4·60, 2·18% total β-glucan and 5·39, 2·06, 1·08% soluble β-glucan contents, respectively, were used in the diets of rats to compare their hypocholesterolaemic effects. Comparison was also made with a standard casein diet. After 40 days of feeding trial, feed intake and weight gain were found to be the highest for the casein diet and differed significantly from those of the barley diets. Dolma (hull-less) based diet, fed to rats caused significant (p<0·05) reductions in the levels of total cholesterol (39%), LDL-cholesterol (61%) and triglyceride (21%), and significant elevation in the level of HDL-cholesterol (34%) in serum compared with the casein diet. Similar changes were observed in liver also. There was a significant increase in the HDLc/TC ratio and decrease in the LDLc/HDLc ratio in the serum and livers of Dolma diet-fed rats. The casein group had the highest total serum protein and liver protein compared with other test groups. Among the test diets, DL-88 had an intermediate and BH-331 the lowest cholesterol-lowering effect. Total and soluble β-glucan appeared to be strong predictors of the cholesterol-lowering in serum and liver of rats. The viscous property of soluble β-glucan may result in reduced absorption, or reabsorption of lipids.

The Long Term Changes in Liver DNA and Total Protein Contents Following Low Level Sarin Exposure in Rats

1. The changes in contents of DNA and total protein in the liver of the rats exposed to low level sarin by inhalation at 3, 6 and 12 months following the exposure were studied. The influence of sarin on the DNA and protein metabolism in liver was determined by the measurements of incorporation of tritiated thymidine into DNA, the concentration of DNA and total protein. 2. Our results show that not only symptomatic level 3 but also asymptomatic levels 1 and 2 of sarin are able to significantly decrease the incorporation of radiolabelled thymidine without changing total concentrations of DNA as well as protein at three months following sarin exposure. On the other hand, the significant decrease in total contents of DNA and protein in liver without the changes in the incorporation of tritiated thymidine was determined in liver six months following sarin exposure. Practically no significant changes in the metabolism of DNA and protein were observed at 12 months following sarin exposure. 3. Thus, not only clinically manifested intoxication but also low-level, asymptomatic exposure to nerve agents such as sarin is able to influence the metabolism of nucleic acids as well as proteins even several months following the exposure.

The Role of Vitamin C Administration in Alleviation of Organ Damage in Rats Infected with Trypanosoma brucei.

The effect of vitamin C supplementation on the development of organ pathology in experimental Trypanosoma brucei infection in rats was investigated. Infection caused significant (p < 0.05) increases in serum alanine and aspartate aminotransferases as well as in blood urea nitrogen and serum creatinine. Infection also caused significant (p < 0.05) hypoproteinemia and hypoalbuminemia as well as decreases in liver and kidney total homogenate proteins. Supplementation of infected rats with vitamin C prevented the disease-induced elevation of serum creatinine and alanine aminotransferase (ALAT) and also significantly ameliorated the decreases in total protein levels in serum, liver, and kidney, as well as the elevated serum aspartate aminotransferase (ASAT). The trypanosome infection caused depletion of the levels of reduced glutathione (GSH) in the blood, liver, and kidney, as well as reduced the plasma level of ascorbic acid. Vitamin supplementation prevented the depletion of these endogenous antioxidants. We concluded that vitamin C supplementation ameliorates oxidative stress, thereby sparing endogenous antioxidant reserves and protecting tissues and organs against T. brucei-induced damage.

Effect of multiple gene transfers of insulinlike growth factor I complementary DNA gene constructs in rats after thermal injury.

Multiple subcutaneous injections of cholesterol-containing cationic liposomes encapsulating the complementary DNA (cDNA) gene for insulinlike growth factor I (IGF-I) increase the rate of transfected skin cells and result in increased IGF-I protein levels in the skin with subsequent improvement in wound healing when compared with a single injection. Laboratory. Twenty-four adult male Sprague-Dawley rats (350-375 g) received a full-thickness scald burn on 60% of their body surface. These rats were randomly divided to receive either 1 injection of liposomes containing 2.2 microg-cytomegalovirus-driven cDNA coding for IGF-I and 0.2 microg of the Lac Z gene cDNA construct, or 2 injections of liposomes containing 2.2 microg cytomegalovirus-driven cDNA coding for IGF-I and 0.2 microg of the Lac Z gene cDNA construct. Transfection rates and IGF-I protein levels in the skin and physiological responses to the IGF-I gene therapy, evaluated from changes in body weight, protein content in serum and liver, and the rate of burn wound healing. There was a significant decrease in transfection rate and IGF-I protein expression distal from the injection site in animals receiving 1 injection, as compared with a consistent increase in rats receiving multiple injections. Multiple injections improved the response to thermal trauma by increasing the extent of the healed burn wound 33 days after thermal injury (single injection, 31% +/- 1% vs multiple injections, 38% +/- 2%), total serum protein (single injection, 52 +/- 0.5 g/L vs multiple injections, 55 +/- 0.6 g/L), and total liver protein (single injection, 82.0 +/- 0.3 mg/mL vs multiple injections, 91.0 +/- 3.8 mg/mL), P<.05. Gene transfer rates can be increased by multiple injections of liposomes encapsulating IGF-I cDNA constructs. Increased transfer results in greater IGF-I protein skin concentrations, accelerated wound healing, and increased serum and liver protein concentrations. The clinical relevance of these findings is that liposomal gene constructs should be applied in well-defined distances to improve gene transfer in the skin, and thus clinical outcome after thermal injury.

Overlapping Distribution of the 130- and 110-kDa Myosin I Isoforms on Rat Liver Membranes

The biochemical and mechanochemical properties and localization of myosin I suggest the involvement of these small members of the myosin superfamily in some aspects of intracellular motility in higher cells. We have determined by quantitative immunoblotting with isoform-specific antibodies that the 130-kDa myosin I (myr 1 gene product) and 110-kDa myosin I (myr 2 gene product) account for 0.5 and 0.4%, respectively, of total rat liver protein. Immunoblot analyses reveal that the 130- and 110-kDa myosins I are found in several purified subcellular fractions from rat liver. The membrane-associated 130-kDa myosin I is found at the highest concentration in the plasma membrane (28 ng/μg plasma membrane protein) followed by the endoplasmic reticulum-like mitochondria-associated membrane fraction (MAM; 10 ng/μg MAM protein), whereas the 110-kDa myosin I is found at the highest concentration in Golgi (50 ng/μg Golgi protein) followed by plasma membrane (20 ng/μg) and MAM (7 ng/μg). Our analyses indicate that myosin I is peripherally associated with Golgi and MAM and its presence in these fractions is not a consequence of myosin I bound to contaminating actin filaments. Although found in relatively low concentrations in microsomes, because of the abundance of microsomes, in liver most of the membrane-associated myosin I is associated with microsomes. Neither myosin I isoform is detected in purified mitochondria. This is the first quantitative analysis addressing the cellular distribution of these mammalian class I myosins.

The combination of growth hormone with hepatocyte growth factor alters the acute phase response.

Recombinant human growth hormone (rhGH) and hepatocyte growth factor (HGF) have both been shown to individually modulate hepatic acute phase reactant proteins and cytokine expression following trauma through different pathways. Recombinant hGH has also been shown to decrease serum and hepatic HGF concentrations after a thermal injury. We hypothesized that the combination of rhGH plus HGF improves the burn-induced acute phase response. Fifty-six male Sprague-Dawley rats received a 60% TBSA third-degree scald burn and were randomly divided to receive either rhGH (2.5 mg/kg/day sc.) plus HGF (200 microg/kg i.v. every 12 h) or placebo (saline). Rats were sacrificed on post-burn days 1, 2, 5, or 7 and serum constitutive and acute phase proteins, TNF-alpha, IL-1beta, IL-6 and liver total protein measured. Hepatic cytokine gene expression, triglyceride concentration, and hepatocyte proliferation were also measured. In rats receiving rhGH/HGF, serum albumin increased on days 5 and 7 and transferrin on day 7 after burn compared to placebo (P<0.05). Haptoglobin decreased 5 days after burn compared to placebo (P<0.05). RhGH/HGF increased serum TNF-alpha on day 2 after burn, while it decreased serum IL-1beta on day 1 after burn compared with placebo (P<0.05). RhGH/HGF had no effect on hepatic cytokine gene expression compared with placebo. Liver total protein content and hepatocyte proliferation increased on days 1, 2, 5, and 7 after burn with rhGH/HGF treatment (P<0.05). These findings indicate that rhGH in combination with HGF exert additive effects on constitutive hepatic proteins and partial inhibitory effects on acute phase protein and cytokine expression. RhGH/HGF has a strong mitogenic effect on hepatocytes.

Inhibition of system A amino acid transport and hepatocyte proliferation following partial hepatectomy in the rat.

System A, the sodium-dependent neutral amino acid transport activity, has a 3-fold increase in its initial uptake velocity into hepatocytes following partial hepatectomy (PH) in the rat. The purpose of this study was to examine the effect of inhibition of System A-mediated amino acid transport on hepatocyte proliferation and liver regeneration. We describe the in vivo competitive inhibition of System A activity following PH by the nonmetabolizable, System A-specific substrate, alpha-(methylamino)isobutyric acid (MeAIB). Administration of MeAIB 60 minutes before PH decreased the incorporation of [(3)H]thymidine into DNA by 45% +/- 5% and 76% +/- 17% at 24 and 36 hours, respectively. The readministration of MeAIB every 12 hours further decreased DNA synthesis by 92% +/- 18% and 82% +/- 11% at 24 and 36 hours. The recovery of liver mass of rats receiving MeAIB was decreased by 46.4% +/- 5.1% at 24 hours after PH. In vitro, 5 mmol/L MeAIB inhibited proliferation of primary hepatocytes by 56% +/- 4% and 61% +/- 12% 48 hours after incubation with 10% fetal calf serum or epidermal growth factor (5 ng/mL), respectively. Thus, MeAIB inhibition of System A transport activity decreased both in vivo and in vitro inducement of hepatocyte proliferation. Treatment with MeAIB did not significantly change the incorporation of [(3)H]leucine into total liver protein, but changes in serum amino acids and hepatocyte cell volume were observed, suggesting System A transport activity during hepatocyte proliferation functions primarily to provide amino acids to fuel liver-specific biochemical pathways and to increase cell volume.

Increased Expression of Insulin-like Growth Factor-I in Serum and Liver after Recombinant Human Growth Hormone Administration in Thermally Injured Rats

Background. Recombinant human growth hormone (rhGH) has been shown to modulate the hypermetabolic response and the hepatic acute-phase response after thermal injury. In vitro studies, however, demonstrated that rhGH activates insulin-like growth factor-I (IGF-I) gene transcription and production, suggesting that rhGH may exert some of its effects indirectly through IGF-I stimulation. The purpose of this study was to determine the effects of rhGH on serum and hepatic IGF-I in thermally injured rats.Methods. Sprague–Dawley rats (56 males) receiving a 60% TBSA third-degree scald burn were randomly divided to receive either rhGH (2.5 mg/kg/day im) or saline (control). Rats were sacrificed on postburn days 1, 2, 5, and 7 and serum IGF-I, hepatic IGF-I mRNA, and IGF-I protein concentration were measured. The physiologic response to changes in IGF-I levels was evaluated by measuring hepatocyte proliferation, total liver protein concentration, and muscle dry/wet weights.Results. Serum IGF-I was increased from postburn day 1 through day 7 in rats receiving rhGH compared to controls (P < 0.05). Hepatic IGF-I mRNA and IGF-I protein expression were increased from day 1 to 7 after burn in animals receiving rhGH when compared to controls (P < 0.05). Recombinant hGH increased hepatocyte proliferation at 5 days and total liver protein concentration at 5 and 7 days postburn compared to controls (P < 0.05). Muscle dry/wet weights increased in rats receiving rhGH at 7 days after burn compared to controls (P < 0.05).Summary. Liver and serum IGF-I levels decreased after a thermal injury. Recombinant hGH attenuated this decrease by stimulating hepatic IGF-I expression. Increases in IGF-I were associated with increases in hepatocyte proliferation and protein concentration in liver and muscle.Conclusion. We suggest that rhGH modulates the hypermetabolic response through IGF-I stimulation in the hepatic parenchyma.

Recombinant Human Growth Hormone Alters Acute Phase Reactant Proteins, Cytokine Expression, and Liver Morphology in Burned Rats

Background.The effects of exogenous recombinant human growth hormone (rhGH) on hepatic acute phase reactant proteins, cytokine expression, and liver morphology were studied in thermally injured rats to define whether rhGH alters the acute phase response.Materials and methods.Sprague-Dawley rats (56 males) receiving a 60% TBSA third-degree scald burn were randomly divided into two groups to receive either 2.5 mg/kg/day sc rhGH or saline. Rats were sacrificed on Postburn Days 1, 2, 5, and 7. Serum acute phase reactant proteins and cytokines TNF-α, IL-1α, IL-1β, and IL-6 were measured. Hepatocyte proliferation, hepatic cytokine gene expression, and liver protein concentrations were determined.Results.Recombinant hGH increased serum albumin on Days 5 and 7 after burn (P< 0.05). Serum haptoglobin and α1-acid glycoprotein levels decreased at 2, 5, and 7 days after burn compared to saline (P< 0.05). In rats treated with rhGH, serum IL-1β decreased 1 day postburn, while serum TNF-α increased 5 days after burn compared to saline (P< 0.05). Serum IL-6 and IL-1α did not change. Hepatic RNA levels for TNF-α were significantly elevated on Day 1 postburn compared to saline (P< 0.05). Hepatic protein content increased on Days 2, 5, and 7 postburn compared to saline (P< 0.05). Hepatocyte proliferation in rhGH-treated rats increased on Day 5 after burn (P< 0.05).Conclusion.Data indicate that rhGH alters the hepatic acute phase response by decreasing type I acute phase proteins and modulating IL-1-like cytokine expression. These changes are associated with increased hepatocyte mitosis and serum and total liver protein concentrations.