GPER1 and breast cancer: To demonstrate that the growth conditions associated with increased GPER1 expression in breast cancer cells also resulted in increased AMPK activation, MCF-7 and T-47D cells were grown in serum-free media containing to 0, 2.5, 5.5 or 25 mM D-glucose for 24 h followed by immunoblot analysis of GPER1, pAMPK (Thr 172) and AMPK protein levels.