activity codetermining ingredient of err 731 u00ae this is all the more surprising since it was previously assumed that only the aglycones but not the glycosylated hydroxystilbenes are active park et al arch pharm res 2002 25 528 533 estrogen receptor u03b2 er u03b2 activation by err 731 u00ae and its metabolites in the er u03b2 expressing endometrial adenocarcinoma cell line hec 1b hec 1b cells a human endometrial adenocarcinoma cell line do not express either er u03b1 or er u03b2 they therefore represent a possible way of investigating in a human and endometrial context ligand dependent effects of substances on the transactivation mechanisms in relation to different receptor subtypes and different estrogen responsive promoters an established er u03b2 mc3 luciferase system was employed for this purpose hec 1b cells were applied in 24 well plates with a density of 95 000 cells well in dulbecco 39 s modified essential medium dmem f12 the next day they were cotransfected with an er u03b2 containing construct her u03b2 psg2 and a triple ere containing promoter luciferase construct mc3 luc pgl2 hillisch et al dissecting physiological roles of estrogen receptor alpha and beta with potent selective ligands from structure based design mol endocrinol 2004 july 18 1599 609 the transient transfection took place using dotap n 1 2 3 dioleoyloxy n n n trimethylammoniumpropane methyl sulfate roth as described by the manufacturer after 24 hours the cells were treated with appropriate concentrations of the substances or substance mixtures to be investigated 170 estradiol e2 10 nm served as positive control and a comparable volume of dimethyl sulfoxide dmso was employed as solvent control the incubation time was 24 hours the cells were then.