Figure 7.

Time course of ET-1–induced decrease in IRS-1 protein. (a) 3T3-L1 adipocytes were incubated in the presence of ET-1 (10 nM) for various time points as indicated (0–24 hours). (b) After pretreatment with LY294002 (25 μM), Rapamycin (20 nM), PD98059 (50 μM), or 0.1% DMSO vehicle for 30 minutes, 3T3-L1 adipocytes were incubated in the absence or presence of ET-1 (10 nM) for 24 hours. Whole-cell lysates were subjected to SDS-PAGE and immunoblotted with anti-IRS-1, anti-Gαq/11, or anti-p110α antibodies, as described in Methods. These experiments were repeated twice.