Figure 4. XMetD is an antagonist of the INSR autophosphorylation. CHO-hINSR cells (B isoform) were preincubated for 30 min at 37 °C with 333 nM of either XMetD or control IgG followed by a 10 min incubation with increasing concentrations of insulin. INSR autophosphorylation was measured by ELISA. Mean ± SD of triplicate determinations are shown.