| The aim of the study was to test the hypothesis that expression of retinoid receptors ( RARalpha , RARbeta , RARgamma ) , rexinoid receptors ( RXRalpha , RXRbeta ) , thyroid hormone receptors ( TRalpha , TRbeta ) , estrogen receptors ( ERalpha , ERbeta ) , nuclear receptor coregulators ( N CoR , SRC 1 , SMRT ) , and in addition type 1 iodothyronine 5 ' deiodinase ( 5 ' DI ) , EGFR and erb B2 / neu would be different in mammary postlactating tissue in comparison with that of nonlactating mammary gland . ^^^ |