ABSTRACT
The pre-implantation embryo of the mouse undergoes a histochemically detectable change in the properties of its trophoblastic cell-surface coat in the immediate pre-implantation period. This change is oestrogen-dependent in vivo and can be induced in vitro in a concentration-dependent manner by oestradiol-17 beta. There is evidence that this coat change is of functional importance in the process of implantation, and its demonstration is of potential value as the basis of an in vitro assay of oestrogenicity.
Subject(s)
Blastocyst/drug effects , Estrogens/pharmacology , Animals , Dose-Response Relationship, Drug , Estradiol/pharmacology , Ethamoxytriphetol/pharmacology , Mice , Organ Culture Techniques , Tamoxifen/pharmacologyABSTRACT
The process of implantation of the blastocyst in utero in the mouse is normally triggered by oestradiol-17 beta. It can, however, be prevented by the drug tamoxifen whose actions in other species are classified as anti-oestrogenic, but which the mouse is held to be a weak oestrogen. Results are presented which support the claim that the anti-implantation action of tamoxifen is dose dependent, oestrogenicity dominating at high doses and anti-oestrogenicity being of major importance at lower doses.
