title: In vitro inhibiton of trophoblast maturation and expansion of early rat blastocysts by an oestrogen antagonist.
abstract: Rat blastocyst development and expansion were studied in an in vitro culture system. Early blastocysts collected from rats on the morning of day 5 were shown to develop normally and underwent expansion when placed in bovine serum albumin supplemented culture medium for 12 h at 37 degrees C. Nafoxidine, an oestrogen antagonist, prevented embryo expansion when added to the culture medium, and it was found that if oestradiol-17 beta was added to this medium this inhibitory effect was removed and the embryos again expanded. Ethanol, used as a solvent for steroids, and cholesterol were added to the medium containing nafoxidine but the blastocysts remained unexpanded after 12 h in culture. These results suggest a need for oestrogen action during blastocyst expansion in vitro. Cultured rat blastocysts were subjected to histochemical study for acid phosphatase (ACPase) and leucylnaphthylamidase (LNAse). In unexpanded blastocysts ACPase was found to be low while LNAse activity was higher when compared with enzyme distribution patterns in expanded blastocysts.
mesh_terms: D000135:Acid Phosphatase / Q000378:metabolism; D000818:Animals; D001755:Blastocyst / Q000187:drug effects* / Q000201:enzymology; D002478:Cells, Cultured; D003470:Culture Media; D004958:Estradiol / Q000502:physiology; D005260:Female; D007931:Leucyl Aminopeptidase / Q000378:metabolism; D008247:Lysosomes / Q000201:enzymology; D009256:Nafoxidine / Q000494:pharmacology*; D011247:Pregnancy; D011759:Pyrrolidines / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D014327:Trophoblasts / Q000187:drug effects* / Q000201:enzymology
chemical_list: D003470:Culture Media; D011759:Pyrrolidines; D009256:Nafoxidine; D004958:Estradiol; D000135:Acid Phosphatase; D007931:Leucyl Aminopeptidase