Assays for Insulin and Insulin-Like Signal Transduction Based on Adipocytes, Hepatocytes, and Myocytes

After having established insulin-like activity of compounds/drug candidates in primary or cultured adipose, muscle, and liver cells or tissues with one or several of the metabolic assays described above (see K.6.1 and K.6.2), it is often useful to elucidate the molecular mode of action of these compounds/drug candidates for further characterization and optimization, in particular regarding selectivity and potency. For this, detailed knowledge in the molecular mechanisms of the insulin signal transduction cascade as well as of cross-talking insulin-like signaling pathways as well as the availability of appropriate reliable and robust cell-free and cell-based assays reflecting these events is required. The following view results from the current experimental findings but, due to limitations in space and rapid progress still made in this area, has to be considered as simplified and temporary, only