LEP and Insulin resistance: Quantification of gene expression of factors critical for adipocyte differentiation and function (PPARγ2, C/EBPα, C/EBPβ, leptin, adiponectin, and GLUT4) indicated that SIV infection decreased the expression of most of these genes (Fig. 4a), which may increase the risk for fat redistribution, lipoatrophy, or insulin resistance.