Figure 3.

Leptin has opposite effect on the dynamics of insulin-induced tyrosine phosphorylation of IRS-1 and IRS-2. Cells were serum-starved overnight then treated with or without leptin (Lep; 60 nM) for 10 min, followed by a stimulation with 100 nM insulin (Ins) for 1 or 10 min. IRS protein phosphorylation and p85 binding were assessed as described for Fig. 2. The graphs represent the means of three to eight experiments. A representative blot is shown below each graph.