Inhibition of JNK along with activation of ERK1/2 MAPK pathways improve steatohepatitis among the rats

Chinese herbal medicines: The modulator of nonalcoholic fatty liver disease targeting oxidative stress

ETHNOPHARMACOLOGICAL RELEVANCE

Plants are a natural treasure trove; their secondary metabolites participate in several pharmacological processes, making them a crucial component in the synthesis of novel pharmaceuticals and serving as a reserve resource foundation in this process. Nonalcoholic fatty liver disease (NAFLD) is associated with the risk of progression to hepatitis and liver cancer. The "Treatise on Febrile Diseases," "Compendium of Materia Medica," and "Thousand Golden Prescriptions" have listed herbal remedies to treat liver diseases.

AIM OF THE REVIEW

Chinese herbal medicines have been widely used for the prevention and treatment of NAFLD owing to their efficacy and low side effects. The production of reactive oxygen species (ROS) during NAFLD, and the impact and potential mechanism of ROS on the pathogenesis of NAFLD are discussed in this review. Furthermore, common foods and herbs that can be used to prevent NAFLD, as well as the structure-activity relationships and potential mechanisms, are discussed.

METHODS

Web of Science, PubMed, CNKI database, Google Scholar, and WanFang database were searched for natural products that have been used to treat or prevent NAFLD in the past five years. The primary search was performed using the following keywords in different combinations in full articles: NAFLD, herb, natural products, medicine, and ROS. More than 400 research papers and review articles were found and analyzed in this review.

RESULTS

By classifying and discussing the literature, we obtained 86 herbaceous plants, 28 of which were derived from food and 58 from Chinese herbal medicines. The mechanism of NAFLD was proposed through experimental studies on thirteen natural compounds (quercetin, hesperidin, rutin, curcumin, resveratrol, epigallocatechin-3-gallate, salvianolic acid B, paeoniflorin, ginsenoside Rg1, ursolic acid, berberine, honokiol, emodin). The occurrence and progression of NAFLD could be prevented by natural antioxidants through several pathways to prevent ROS accumulation and reduce hepatic cell injuries caused by excessive ROS.

CONCLUSION

This review summarizes the natural products and routinely used herbs (prescription) in the prevention and treatment of NAFLD. Firstly, the mechanisms by which natural products improve NAFLD through antioxidant pathways are elucidated. Secondly, the potential of traditional Chinese medicine theory in improving NAFLD is discussed, highlighting the safety of food-medicine homology and the broader clinical potential of multi-component formulations in improving NAFLD. Aiming to provide theoretical basis for the prevention and treatment of NAFLD.

A Study on the Therapeutic Efficacy of San Zi Yang Qin Decoction for Non-Alcoholic Fatty Liver Disease and the Underlying Mechanism Based on Network Pharmacology

OBJECTIVE

This study aims to explore the therapeutic efficacy of San Zi Yang Qin Decoction (SZ) and its potential mechanism in the treatment of non-alcoholic fatty liver disease (NAFLD) based on network pharmacology and in vivo experiments.

METHODS

Effective chemicals and targets of SZ were searched in online databases, according to the drug-likeness of compounds and the binomial distribution of targets. A disease-target-chemical network was established using NAFLD-associated genes screened through GeneCards database, Gene Ontology (GO) terms, and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways. Furthermore, animal experiments were conducted to verify the efficacy and mechanism of SZ predicted by network pharmacology. The NAFLD mouse model was established with C57BL/6J mice fed with a high-fat diet for 22 weeks. The mice in the control group were fed with a chow diet. From the 23rd week, the NAFLD mice were treated with intragastric SZ or normal saline for 8 weeks. After the glucose tolerance was measured, the mice were sacrificed, followed by the collection of serum and liver tissues. Pathological changes in liver tissues were examined by H&E staining. Additionally, alanine aminotransferase (ALT), aspartate aminotransferase (AST), serum fast blood glucose, and insulin levels were detected. Expression levels of TNF-α of serum and liver tissues were determined by ELISA and qRT-PCR, respectively. Western blot was used to detect the activation of AKT in liver tissues.

RESULTS

A total of 27 effective compounds and 20 targets of SZ were screened. GO analysis uncovered a significant correlation between the targets of SZ and those of NAFLD. KEGG analysis presented the signaling pathways enriched in SZ and NAFLD, including NAFLD, TNF-α, and apoptosis pathways. The area under the curve of major GO and KEGG pathways indicated the potential role of SZ in improving NAFLD. In vivo experiments demonstrated that SZ significantly alleviated hepatosteatosis and inflammatory cell infiltration in liver tissues, reduced serum transaminases, and improved insulin resistance and glucose tolerance of NAFLD mice. The protein level of phospho-AKT was upregulated by SZ. Additionally, SZ treatment obviously impaired the TNF-α level in the serum and liver tissue of NAFLD mice.

CONCLUSIONS

According to the network pharmacology analysis and in vivo experiments, SZ could have therapeutic efficacy for NALFD. The mechanism mainly involves pathways relative to insulin resistance, TNF-α, and apoptosis. Our results provide a scientific basis for SZ in the clinical treatment of NAFLD.

Involvement of G protein-coupled receptor kinase 2 (GRK2) in the development of non-alcoholic steatosis and steatohepatitis in mice and humans

Insulin resistance (IR) and obesity are important risk factors for non-alcoholic fatty liver disease (NAFLD). G protein-coupled receptor kinase 2 (GRK2) is involved in the development of IR and obesity in vivo. However, its possible contribution to NAFLD and/or non-alcoholic steatohepatitis (NASH) independently of its role on IR or fat mass accretion has not been explored. Here, we used wild-type (WT) or GRK2 hemizygous (GRK2±) mice fed a high-fat diet (HFD) or a methionine and choline-deficient diet (MCD) as a model of NASH independent of adiposity and IR. GRK2± mice were protected from HFD-induced NAFLD. Moreover, MCD feeding caused an increased in triglyceride content and liver-to-body weight ratio in WT mice, features that were attenuated in GRK2± mice. According to their NAFLD activity score, MCD-fed GRK2± mice were diagnosed with simple steatosis and not overt NASH. They also showed reduced expression of lipogenic and lipid-uptake markers and less signs of inflammation in the liver. GRK2± mice preserved hepatic protective mechanisms as enhanced autophagy and mitochondrial fusion and biogenesis, together with reduced endoplasmic reticulum stress. GRK2 protein was increased in MCD-fed WT but not in GRK2± mice, and enhanced GRK2 expression potentiated palmitic acid-triggered lipid accumulation in human hepatocytes directly relating GRK2 levels to steatosis. GRK2 protein and mRNA levels were increased in human liver biopsies from simple steatosis or NASH patients in two different human cohorts. Our results describe a functional relationship between GRK2 levels and hepatic lipid accumulation and implicate GRK2 in the establishment and/or development of NASH.

Teucrium polium L. Improved Heart Function and Inhibited Myocardial Apoptosis in Isolated Rat Heart Following Ischemia-Reperfusion Injury

OBJECTIVES

Myocardial reperfusion is the only logical cure for ischemic heart disease. However, ischemic-reperfusion (I/R) injury is one of the underlying factors facilitating and accelerating the apoptosis in the myocardium. This study set to investigate the impact of Teucrium polium (TP) hydro-alcoholic extract on I/R induced apoptosis in the isolated rat heart.

METHODS

Isolated rat hearts were classified into six groups. The control samples were subjected to 80 min of perfusion with Krebs-Henseleit bicarbonate (KHB) buffer; in control-ischemia group, after primary perfusion (20 min) the hearts were exposed to global ischemia (20 min) and reperfusion (40 min). Pretreated groups were perfused with 500 μM of vitamin C and various TP concentrations (0.5, 1, 2 mg/ml) for 20 min, and then the hearts were exposed to ischemia and reperfusion for 20 min and 40 min, respectively. Cardiodynamic parameters including rate pressure product (RPP), heart rate (HR), the maximum up/down rate of left ventricular pressure (±dp/dt), left ventricular developed pressure (LVDP), and coronary artery flow (CF) were achieved from Lab Chart software data. The Bax and BCl-2 gene expressions were measured in heart samples.

RESULTS

Hearts treated with TP extract and vit C represented a meaningful improvement in cardiac contractile function and CF. The overexpression of Bcl-2, downregulation of Bax, and improvement of apoptotic index (Bax/Bcl-2) were observed in pretreated TP extract and vit C hearts.

CONCLUSION

The TP extract was found to ameliorate the cardiac function in the reperfused myocardium. Also, it can hinder apoptotic pathways causing cardioprotection.

Hepatocyte-specific deletion of LASS2 protects against diet-induced hepatic steatosis and insulin resistance

Homo sapienslongevity assurance homolog 2 of yeast LAG1 (LASS2) is expressed mostly in human liver. Here, we explored roles of LASS2 in pathogenesis of hepatic steatosis. Hepatocyte-specific LASS2 knockout (LASS2^-/-) mice were generated using Cre-LoxP system. LASS2^-/- and wild-type (WT) mice were fed with chow or high-fat diet (HFD). We found LASS2^-/- mice were resistant to HFD-induced hepatic steatosis and insulin resistance. In HFD-fed mice, LASS2 deficiency significantly inhibited p38 MAPK and ERK1/ERK2 signaling in mouse liver. This effect was mediated by a significant increase of V-ATPase activity and a decrease of ROS level. We also observed that elevated expression of LASS2 in mouse hepatocyte cell line AML12 obviously decreased V-ATPase activity and increased ROS level by activation of p38 MAPK and ERK1/ERK2 signaling. Our findings indicate that LASS2 plays an important role in the pathogenesis of diet-induced hepatic steatosis and is a potential novel target for prevention and intervention of liver diseases.

Deletion of Gab2 in mice protects against hepatic steatosis and steatohepatitis: a novel therapeutic target for fatty liver disease

Fatty liver disease is a serious health problem worldwide and is the most common cause for chronic liver disease and metabolic disorders. The major challenge in the prevention and intervention of this disease is the incomplete understanding of the underlying mechanism and thus lack of potent therapeutic targets due to multifaceted and interdependent disease factors. In this study, we investigated the role of a signaling adaptor protein, GRB2-associated-binding protein 2 (Gab2), in fatty liver using an animal disease model. Gab2 expression in hepatocytes responded to various disease factor stimulations, and Gab2 knockout mice exhibited resistance to fat-induced obesity, fat- or alcohol-stimulated hepatic steatosis, as well as methionine and choline deficiency-induced steatohepatitis. Concordantly, the forced expression or knockdown of Gab2 enhanced or diminished oleic acid (OA)- or ethanol-induced lipid production in hepatocytes in vitro, respectively. During lipid accumulation in hepatocytes, both fat and alcohol induced the recruitment of PI3K or Socs3 by Gab2 and the activation of their downstream signaling proteins AKT, ERK, and Stat3. Therefore, Gab2 may be a disease-associated protein that is induced by pathogenic factors to amplify and coordinate multifactor-induced signals to govern disease development in the liver. Our research provides a novel potential target for the prevention and intervention of fatty liver disease.

Punicalagin attenuates palmitate-induced lipotoxicity in HepG2 cells by activating the Keap1-Nrf2 antioxidant defense system

SCOPE

Free fatty acids (FFA) could induce hepatocyte lipotoxicity, which plays an important role in the initiation of nonalcoholic fatty liver disease (NAFLD). Inhibition of FFA-induced lipotoxicity is suggested as a potential treatment for nonalcoholic fatty liver disease. The aim of the current study is to explore the effect of punicalagin, a polyphenol abundant in pomegranate, on FFA-induced hepatic lipotoxicity and its potential mechanisms.

METHODS AND RESULTS

HepG2 cells were exposed to 250 μM palmitate for 24 h with or without punicalagin pretreatment. Punicalagin pretreatment attenuated palmitate-induced mitochondrial membrane potential lost, ATP depletion, and reactive oxygen species production. Punicalagin also increased hepatocyte viability by blocking mitochondria-mediated caspase-dependent apoptosis. The hepatoprotective effect was associated with an exaggerated phosphorylation of extracellular signal regulated kinase as well as significant nuclear factor erythroid 2-related factor 2 (Nrf2) nuclear translocation and target genes induction. Blockage of extracellular signal regulated kinase by a pharmacological inhibitor abrogated the cytoprotective effect of punicalagin and its induction of Nrf2 pathway. Knockdown of Nrf2 by specific small interfering RNA also diminished the protective effects of punicalagin, while knockdown of Kelch-like ECH-associated protein 1 (Keap1) with small interfering RNA could promote Nrf2 nuclear translocation and exert similar protection as punicalagin treatment.

CONCLUSIONS

These findings suggest that punicalagin could effectively attenuate FFA-induced lipotoxicity by activating Keap1-Nrf2 cytoprotective signaling pathway.

The Ethanol Extract from Lonicera japonica Thunb. Regresses Nonalcoholic Steatohepatitis in a Methionine- and Choline-Deficient Diet-Fed Animal Model

Nonalcoholic steatohepatitis (NASH) is characterized as fat accumulation in the hepatic tissue associated with various degrees of inflammation and progressive fibrosis. The potent anti-inflammatory and ethnopharmacological properties of Lonicera japonica Thunb. (Caprifoliaceae) make it an excellent source of novel medicinal targets for the treatment of NASH. The aim of the study was to investigate the effects of L. japonica ethanol extract (LJEE) on NASH in mice. C57BL/6J mice were fed with methionine-choline-deficient diet (MCDD) for eight weeks to promote the development of NASH. After development of the model, the mice were administered LJEE once daily via oral gavage at doses of 100, 200, or 300 mg/kg for another four weeks. Simultaneous treatments with LJEE (300 mg/kg/day) resulted in pronounced improvements in liver steatosis, ballooning degeneration, and inflammation. LJEE prevented MCDD-induced plasma level increases in aspartate aminotransferase and alanine aminotransferase. LJEE significantly reduced hepatic malondialdehyde level and ameliorated hepatic inflammation and fibrosis in MCDD-fed mice, which were associated with down-regulation of cytochrome P450 2E1 suppression of multiple proinflammatory and profibrotic genes. LJEE can prevent hepatic steatosis by reducing hepatic peroxisome acyl-CoA:diacylglycerol acyltransferase 2 expression, as well as by inducing proliferator-activated receptor α expression. In addition, the LJEE treatments caused significant reduction in the phosphorylated form of Jun N-terminal kinase along with an increase in the phosphorylated level of extra cellular signal-regulated kinase 1/2. Our study demonstrated the protective role of LJEE in ameliorating nutritional steatohepatitis.

Repression of the nuclear receptor small heterodimer partner by steatotic drugs and in advanced nonalcoholic fatty liver disease

The small heterodimer partner (SHP) (NR0B2) is an atypical nuclear receptor that lacks a DNA-binding domain. It interacts with and inhibits many transcription factors, affecting key metabolic processes, including bile acid, cholesterol, fatty acid, and drug metabolism. Our aim was to determine the influence of steatotic drugs and nonalcoholic fatty liver disease (NAFLD) on SHP expression and investigate the potential mechanisms. SHP was found to be repressed by steatotic drugs (valproate, doxycycline, tetracycline, and cyclosporin A) in cultured hepatic cells and the livers of different animal models of NAFLD: iatrogenic (tetracycline-treated rats), genetic (glycine N-methyltransferase-deficient mice), and nutritional (mice fed a methionine- and choline-deficient diet). Among the different transcription factors investigated, CCAAT-enhancer-binding protein α (C/EBPα) showed the strongest dominant-repressive effect on SHP expression in HepG2 and human hepatocytes. Reporter assays revealed that the inhibitory effect of C/EBPα and steatotic drugs colocalize between -340 and -509 base pair of the SHP promoter, and mutation of a predicted C/EBPα response element at -473 base pair abolished SHP repression by both C/EBPα and drugs. Moreover, inhibition of major stress signaling pathways demonstrated that the mitogen-activated protein kinase kinase 1/2 pathway activates, while the phosphatidylinositol 3 kinase pathway represses SHP in a C/EBP-dependent manner. We conclude that SHP is downregulated by several steatotic drugs and in advanced NAFLD. These conditions can activate signals that target C/EBPα and consequently repress SHP, thus favoring the progression and severity of NAFLD.

Herbal medicines for the treatment of nonalcoholic steatohepatitis: current scenario and future prospects

Nonalcoholic steatohepatitis (NASH) is a multifactorial disease and has close correlations with other metabolic disorders. This makes its treatment difficult using a single pharmacological drug. Use of plant extract/decoction or polyherbal formulation to treat various liver diseases is very well mentioned in various traditional systems of medicine (Ayurveda, Japanese or traditional Chinese Medicine, and Kampo medicine). Medicinal herbs are known for their multifaceted implications and thus can form an effective treatment schedule against NASH. Till date, several plant extracts, polyherbal formulations, and phytochemicals have been evaluated for their possible therapeutic potential in preventing onset and progression of NASH in experimental models, but clinical studies using the same are sparse. Herbal extracts with antioxidants, antidiabetic, and antihyperlipidemic properties have been shown to ameliorate symptoms of NASH. This review article is a meticulous compilation of our current knowledge on the role of natural products in alleviating NASH and possible lacunae in research that needs to be addressed.

Evolving concepts in the pathogenesis of NASH: beyond steatosis and inflammation

Non-alcoholic steatohepatitis (NASH) is characterised by hepatic steatosis and inflammation and, in some patients, progressive fibrosis leading to cirrhosis. An understanding of the pathogenesis of NASH is still evolving but current evidence suggests multiple metabolic factors critically disrupt homeostasis and induce an inflammatory cascade and ensuing fibrosis. The mechanisms underlying these changes and the complex inter-cellular interactions that mediate fibrogenesis are yet to be fully elucidated. Lipotoxicity, in the setting of excess free fatty acids, obesity, and insulin resistance, appears to be the central driver of cellular injury via oxidative stress. Hepatocyte apoptosis and/or senescence contribute to activation of the inflammasome via a variety of intra- and inter-cellular signalling mechanisms leading to fibrosis. Current evidence suggests that periportal components, including the ductular reaction and expansion of the hepatic progenitor cell compartment, may be involved and that the Th17 response may mediate disease progression. This review aims to provide an overview of the pathogenesis of NASH and summarises the evidence pertaining to key mechanisms implicated in the transition from steatosis and inflammation to fibrosis. Currently there are limited treatments for NASH although an increasing understanding of its pathogenesis will likely improve the development and use of interventions in the future.

Immune therapy for nonalcoholic steatohepatitis: are we there yet?

Metabolic syndrome, obesity, and nonalcoholic steatohepatitis are associated with a state of chronic inflammation. The immune system and the inflammatory cascade can be involved in the development of any of the above common conditions. This association raises the question of whether immune therapy can be used for the treatment of nonalcoholic steatohepatitis. Although immune therapy is not yet feasible for clinical use, here, we review some of the recent data on the potential role of the various arms of the immune system in the development of nonalcoholic steatohepatitis and several potential therapeutic targets.

Quercetin treatment ameliorates inflammation and fibrosis in mice with nonalcoholic steatohepatitis

We investigated whether quercetin protects from steatosis and limits the expression of proinflammatory and fibrogenic genes in C57BL/6J mice with nonalcoholic steatohepatitis (NASH) induced by feeding a methionine-choline-deficient (MCD) diet. Quercetin (50 mg/kg) was given by oral route daily. Mice were randomly divided into 4 groups that received for 2 or 4 wk: the control diet plus vehicle, control diet plus quercetin, MCD diet plus vehicle, and MCD diet plus quercetin. At both 2 and 4 wk, feeding the MCD diet resulted in liver steatosis, inflammatory cell accumulation, oxidative stress evaluated by the concentration of TBARS, and fibrosis evidenced by the staining of α-smooth muscle actin-positive cells in the liver. At both 2 and 4 wk, the MCD diet induced an increase in the mRNA levels of Il6, Tnf, Ptgs2, and Hmgb1 and increased the protein concentrations of Toll-like receptor-4, c-Jun terminal kinase, and p65 NFκB subunit compared with control rats. Feeding the mice the MCD diet also triggered an increase of Col1a1, Col3a1, Plod3, Tgfb1, Smad3, Smad7, Pdgfb, Ctgf, Areg, Mmp9, and Timp1 mRNA levels. These effects were totally or partially prevented by treatment with quercetin. The data obtained suggest that attenuation of multiple profibrotic and proinflammatory gene pathways contributes to the beneficial effects of quercetin in mice with MCD diet-induced steatohepatitis.

Silybin combined with phosphatidylcholine and vitamin E in patients with nonalcoholic fatty liver disease: a randomized controlled trial

The only currently recommended treatment for nonalcoholic fatty liver disease (NAFLD) is lifestyle modification. Preliminary studies of silybin showed beneficial effects on liver function. Realsil (RA) comprises the silybin phytosome complex (silybin plus phosphatidylcholine) coformulated with vitamin E. We report on a multicenter, phase III, double-blind clinical trial to assess RA in patients with histologically documented NAFLD. Patients were randomized 1:1 to RA or placebo (P) orally twice daily for 12 months. Prespecified primary outcomes were improvement over time in clinical condition, normalization of liver enzyme plasma levels, and improvement of ultrasonographic liver steatosis, homeostatic model assessment (HOMA), and quality of life. Secondary outcomes were improvement in liver histologic score and/or decrease in NAFLD score without worsening of fibrosis and plasma changes in cytokines, ferritin, and liver fibrosis markers. We treated 179 patients with NAFLD; 36 were also HCV positive. Forty-one patients were prematurely withdrawn and 138 patients analyzed per protocol (69 per group). Baseline patient characteristics were generally well balanced between groups, except for steatosis, portal infiltration, and fibrosis. Adverse events (AEs) were generally transient and included diarrhea, dysgeusia, and pruritus; no serious AEs were recorded. Patients receiving RA but not P showed significant improvements in liver enzyme plasma levels, HOMA, and liver histology. Body mass index normalized in 15% of RA patients (2.1% with P). HCV-positive patients in the RA but not the P group showed improvements in fibrogenesis markers. This is the first study to systematically assess silybin in NAFLD patients. Treatment with RA but not P for 12 months was associated with improvement in liver enzymes, insulin resistance, and liver histology, without increases in body weight. These findings warrant further investigation.

Anti-apoptotic and anti-inflammatory effects of Silybum marianum in treatment of experimental steatohepatitis

In this study, we were aimed to evaluate the probable effect of the crud extract of Silybum marianum, with high polyphenolic content, on experimental nonalcoholic steatohepatitis (NASH). To induce NASH, a methionine and choline deficient (MCD) diet was given to N-Mary rats for 8 weeks. After NASH development, MCD-fed rats were divided into two groups: MCD groups received MCD diet and MCD+S group was fed MCD diet plus crude extract of S. marianum orally for 3 weeks. Control group was fed a normal diet for 11 weeks. Finally, all rats were sacrificed. Plasma alanine amino transferase (ALT) and aspartate amino transferase (AST) levels were evaluated. In addition, the following hepatic factors were also evaluated: liver histology, malondialdehyde (MDA) and reduced glutathione (GSH) contents, gene expressions of TNF-α and TGF-β and immunoblot evaluations of caspase-3, ERK/p-ERK, JNK/pJNK and p38/pp38. Histopathological evaluations of the liver samples revealed that treatment with the S. marianum extract has abated the severity of NASH among the MCD-fed rats. Also, a significant reduction was observed in the sera ALT and AST activities. In addition, the extract caused dramatic reduction in the elevated hepatic TNF-α and TGF-β mRNA and MDA levels along with an increase in the GSH content. Moreover, the plant extract treatments significantly lowered activation of procaspase-3 to active caspase-3 and also lowered the phosphorylated form of JNK among the same group of rats. These results suggest that the S. marianum crude extract beneficial effects on NASH are mainly due to its antioxidant and anti-inflammatory activities.

Preventive effects of chronic exogenous growth hormone levels on diet-induced hepatic steatosis in rats

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD), which is characterized by hepatic steatosis, can be reversed by early treatment. Several case reports have indicated that the administration of recombinant growth hormone (GH) could improve fatty liver in GH-deficient patients. Here, we investigated whether chronic exogenous GH levels could improve hepatic steatosis induced by a high-fat diet in rats, and explored the underlying mechanisms.

RESULTS

High-fat diet-fed rats developed abdominal obesity, fatty liver and insulin resistance. Chronic exogenous GH improved fatty liver, by reversing dyslipidaemia, fat accumulation and insulin resistance. Exogenous GH also reduced serum tumour necrosis factor-alpha (TNF-alpha) levels, and ameliorated hepatic lipid peroxidation and oxidative stress. Hepatic fat deposition was also reduced by exogenous GH levels, as was the expression of adipocyte-derived adipokines (adiponectin, leptin and resistin), which might improve lipid metabolism and hepatic steatosis. Exogenous GH seems to improve fatty liver by reducing fat weight, improving insulin sensitivity and correcting oxidative stress, which may be achieved through phosphorylation or dephosphorylation of a group of signal transducers and activators of hepatic signal transduction pathways.

CONCLUSIONS

Chronic exogenous GH has positive effects on fatty liver and may be a potential clinical application in the prevention or reversal of fatty liver. However, chronic secretion of exogenous GH, even at a low level, may increase serum glucose and insulin levels in rats fed a standard diet, and thus increase the risk of insulin resistance.