TI - Dose -dependent activation of ERK1/2 by 17beta-estradiol is influenced by the level of membrane ER-alpha expression . AB - In mERhigh cells , the ability of E2 to induce ERK activation was biphasic with respect to dose at the 10 min time point ( early response peak ) . ERK phosphorylaTION was stimulated at a wide range of concentrations from 0.1 pmol/l to 100 nmol/l E2 , although the highest E2 concentrations resulted in less PHOSphorylation ( Fig 8a ) . In mERlow cells a biphasic response was also seen , but the only effective concentrations were 0.1 and 1 pmol/l for the 6 min ( early and only ) response peak ( Fig 8b ) .