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

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.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.Non-alcoholic fatty liver disease (NAFLD) is a metabolic disorder characterized by fatty infiltration of the liver in the absence of alcohol consumption. It is the most common cause of chronic liver disease and represents a spectrum of liver diseases, which include simple fatty liver, steatohepatitis, and cirrhosis [1]. NAFLD is present in 10-24% of the world's population and its prevalence is even greater in obese individuals, ranging from 57.5 to 74.0%.Hepatic steatosis is a hallmark of NAFLD and is caused by the accumulation of lipids, particularly triglycerides, in the liver. Hepatic steatosis, usually considered as an early stage of NAFLD, is generally benign, relatively non-aggressive and reversible. The symptoms are not obvious and the disease is often overlooked. However, because hepatic steatosis can