Growth Arrest-Specific 6 Modulates Adiponectin Expression and Insulin Resistance in Adipose Tissue.

AIMS/INTRODUCTION Obesity is characterized by disturbed adipocytokine expression and insulin resistance in adipocytes. Growth arrest-specific 6 (GAS6) is a gene encoding the Gas6 protein, which is expressed in fibroblasts, and its related signaling may be associated with adipose tissue inflammation, glucose intolerance and insulin resistance. The aim of this study was to investigate the associations among Gas6, adipocytokines and insulin resistance in adipocytes. MATERIALS AND METHODS Mature SGBS adipocytes were treated with high levels of insulin to mimic insulin resistance, and examined for the expressions of Gas6, cytokines and adipocytokines from preadipocytes in differentiation. In an animal study, high-fat diet-induced obese mice were used to verify the Gas6 expression in vitro. RESULTS During the differentiation of adipocytes, the expression of Gas6 gradually decreased and was obviously down regulated with adipocyte inflammation and insulin resistance. Gas6 levels were found to be in proportion to the expression of adiponectin, which has been regarded as closely relevant to improved insulin sensitivity after metformin treatment. Similar results were also confirmed in the animal study. CONCLUSIONS Our results suggest that Gas6 may modulate the expression of adiponectin and may therefore be associated with insulin resistance in adipose tissues.