ITLN1 and obesity due to melanocortin 4 receptor deficiency: Therefore, due to the probable potential role of omentin as an insulin sensitizer, the predominant expression of omentin in adipose tissue and its presence in circulation, it was decided to determine the serum omentin levels and the related gene expression in animal models as normal subjects, T1D, T2D with normal weight as well as obesity, and analyze the relationship between omentin gene expression levels with plasma glucose, insulin, omentin, and other biochemical parameters.