Background and study aim: Previous works have revealed that adipose tissue functions as an endocrine organ, producing a variety of adipokines. These so-called adipokines play important roles in metabolic homeostasis, and when their production is not properly regulated, they can contribute to metabolic diseases. Omentin is a novel adipokine secreted from visceral omental fatand others. Evidence suggests that omentin is one of the factors involved in the complex network that controls insulin resistance, obesity and diabetes. We aimed to evaluate the effects of in vivo administration of omentinon glucose and lipid metabolism in normal conditions and in experimentally induced type 2 diabetes mellitus.
Material and Methods: In this work, 60 adult male white albino rats were divided into 6 equal groups each group contains 10 animals. These groups are control, omentin injected, obese/diabetic, obese/diabetic omentin injected, obese/diabetic insulin injected and obese/diabetic insulin and omentin injected groups. The effect of omentin on metabolic parameters was reflected by analysis of fasting serum glucose, insulin and HOMA IR and HOMA β. Also, full analysis for lipid profile including total cholesterol, LDL-cholesterol, triglycerides and HDL-cholesterol was performed. Parallel to analytic studies, anthropometric measures were obtained in the form of body mass index (BMI) and waist circumference.
Results: There were significant decreases in serum levels of glucose in obese/diabetic omentin injected and obese/diabetic insulin and omentin injected group (P< 0.001, P< 0.001 respectively). But, this effect was insignificant in omentin injected animals when compared with control. Likewise, there were significant decreases in HOMA IR in obese/diabetic omentin injected and obese/diabetic insulin and omentin injected group (P< 0.001, P< 0.001 respectively). In addition, there were significant increases in HOMA βin obese/diabetic omentin injected and obese/diabetic insulin and omentin injected group (P< 0.001, P< 0.001 respectively).
In obese/diabetic animals, injection of omentin resulted in a significant decrease in total cholesterol, LDL and triglycerides, together with a significant increase in HDL.
Conclusion: We can conclude that, the insulin sensitizer effect of omentin improves both glucose tolerance and dyslipidemia in cases of type 2 diabetes but not in the normal conditions.