Fig. 1. Tyrosine phosphorylation of the insulin receptor in 3T3-L1 adipocyte cells. 3T3-L1 adipocytes were stimulated with various concentrations of insulin or methylhydroxychalcone polymer (MHCP) for 30 minutes, washed and lysed. The insulin receptor ß subunit was immunoprecipitated, separated by SDS-PAGE and transferred to PVDF membrane. The receptor was probed with antiphosphotyrosine antibodies and detection was with chemiluminescence.