A variety of these lipid species, including diacylglycerides (DAGs), free fatty acids (FFAs), sphingolipids, and ceramides, can contribute to insulin resistance by stimulating various serine/threonine kinases, including members of the novel PKC family, resulting in increased serine/threonine phosphorylation of the insulin receptor (IR) substrates IRS1 and IRS2, the IR, and other proteins, which collectively lead to decreased insulin action (18, 19). This evidence concerns the gene INS and Insulin resistance.