Antibodies to estradiol receptor from human myometrium

Abstract

Sera raised in sheep immunised with human myometrial estradiol receptor purified by affinity chromatography on an estradiol-hemisuccinate matrix have been shown to contain antibodies to cytoplasmic estradiol receptor (R e). Ultracentrifugation studies in sucrose gradients indicated that R E-antisera crossreacted with [ 3H]-estradiol-labelled cytoplasmic R E components from human uterus, breast tumors and MCF-7 cells, rat uterus and pituitary gland and calf uterus. R E-antibodies did not react with either human or rat progesterone receptors, dihydrotestosterone receptors from human breast tumours or rat ventral prostate, sex steroid binding globulin from human plasma or rat α-foetoprotein. No crossreaction could be detected between the antisera and calcium stabilized (4.6S) or trypsinized (4S) forms of rat uterine R E or with the 5S nuclear r e component from rat uterus. As the antisera cross-reacts with eytoplasmic rat uterine and pituitary 4S R E in high salt sucrose gradients, absence of immunocomplex formation with proteolytically digested rat uterine r e may indicate loss of antigenic determinants from these subunits.