OBJECTIVE: In the following study, we investigated treatment-related changes in mammary gland histomorphology and structure after the administration of soy to adult virgin ovariectomized (OVX) female @entity35 . Additionally, mammary receptor regulation was extensively evaluated by immunohistochemical analysis, and tissue proliferative activity analyzed by cell nuclear proliferating antigen expression (Ki67). DESIGN: OVX @entity35 were treated, for 6 weeks, with either the vehicle, the soy extract (SSE 100 mg/kg/d PO), or @entity53 (0.5 mg/kg/d PO); a sham control group (SHAM) was also included in the study. When killed, mammary glands were collected and subsequently processed for light microscopy or immunohistochemistry. Immunoreactivity was quantified by a scoring system that took into account both the percentage of positive cells and the intensity of the staining. RESULTS: The @entity53 --treated @entity35 had stimulated mammary glands compared with OVX @entity35 , with an average lobulo-alveolar development not different from the SHAM controls. Only a partial regression of the glandular atrophy was observed in OVX @entity35 receiving 100 mg/kg/d SSE, with a histological appearance between that of the OVX and SHAM controls. No significant changes were observed among experimental groups in the median @entity7605 scores of the epithelial compartment (score of 3 in all groups); in the stromal compartment, a tendency toward decreased expression was seen with @entity53 @entity35 compared with OVX controls (scores of 2 and 5, respectively). A significant reduction in @entity12209 immunostaining was observed in the mammary glands of SSE-treated @entity35 , in both epithelium and stroma (scores of 4 and 3, respectively), compared with those of OVX controls (score of 8 in both compartments). The @entity12209 receptor status was not significantly affected by @entity53 . Compared with OVX @entity35 (score of 1), PR expression was up-regulated by @entity53 (score of 6), whereas an ovariectomy-like pattern was observed after the administration of SSE (score of 0). Ki67 immunoreactivity in the epithelium and stroma was increased by the administration of @entity53 (scores of 4 and 5, respectively) and was unchanged after SSE treatment (scores of 0 and 2, respectively), compared with OVX controls (scores of 1 and 2, respectively). CONCLUSIONS: The differences observed in the histological pattern, hormonal receptor status regulation, and Ki67 modulation suggest a different role for phytoestrogens and @entity53 in postmenopausal rodent mammary glands.

XXXX and phytoestrogens differently influence the rodent postmenopausal mammary gland.

@entity35 :: ('10116', 'Species') :: ['rats'] @entity7605 :: ('24890(Tax:10116)', 'Gene') :: ['ERalpha'] @entity12209 :: ('25149(Tax:10116)', 'Gene') :: ['ERbeta'] @entity53 :: ('MESH:D004958', 'Chemical') :: ['17beta-estradiol']
@entity53 :: (MESH:D004958,Chemical) :: ['Estradiol']
