Effect of somatostatin analog on high-fat diet-induced metabolic syndrome: involvement of reactive oxygen species.

Oxidative stress plays an important role in overnutrition-induced metabolic syndrome. Somatostatin (SST) inhibits a wide variety of physiologic functions in the gastrointestinal tract, which may in turn control the levels of reactive oxygen species (ROS) derived from ingestion of macronutrients. In this study, the involvement of SST in the progression of metabolic syndrome in response to a high-fat diet (HFD) was investigated. Male C57BL/6 mice were fed either a normal diet (4.89% fat) or a high-fat diet (21.45% fat) for 4 weeks. The SST analog octreotide (20 microg/kg/day) was then administered intraperitoneally to half of the HFD mice throughout the 10-day experimental period. Body weight, adipose tissue weight, gastric acidity, total bile acid, and lipase activity were measured. Plasma lipid, glucose, insulin, SST, the levels of ROS and GSH/GSSG, and lipid peroxidation in the stomach, small intestine, pancreas, and liver were also evaluated. Following HFD intake for 38 days, a decrease in the plasma levels of SST and GSH/GSSG ratio was observed, while there was an increase in body weight, adipose tissue weight, plasma glucose, triglyceride, and levels of ROS and lipid peroxidation of the stomach, small intestine, pancreas, and liver. However, simultaneous administration of SST analog octreotide to HFD-fed mice significantly reduced ROS production of the digestive system and resulted in the improvement of all the aforesaid adverse changes, suggesting the involvement of SST in the progression of HFD-induced metabolic syndrome.