Figure 4

Alteration of insulin signaling cascades in heart tissue of rats after MI. Tyrosine phosphorylation of IR β-subunit and IRS1 and serine phosphorylation of Akt (ser 473). Heart muscle tissue lysates were subjected to immunoprecipitation and/or Western blot using specific antibodies. Left panel, representative immunoblots are shown, Right panel, quantification of phosphorylation blots relative to their corresponding loading. Tyrosine phosphorylation of IR β-subunit relative to IR β-subunit, tyrosine phosphorylation of IRS1 relative to IRS1, serine phosphorylation of Akt (ser 473) relative to Akt. IP immunoprecipitation; IB, immunoblotting; I, insulin (with insulin stimulation); B, basal (without insulin stimulation). Values presented are means ± SEM of 4 to 5 samples in each group. *P < 0.05 versus control group with insulin stimulation. ^#P < 0.05 versus control group without insulin stimulation.