title: Expression of 3 beta-hydroxysteroid dehydrogenase in early bovine embryo development.
abstract: We analyzed the presence of 3 beta-Hydroxysteroid Dehydrogenase/Delta(5-->4)-isomerase enzyme (3 beta-HSD) activity, a key enzyme of the steroid metabolic pathway, the mRNA of this enzyme, and the steroid metabolism in in vitro produced bovine embryos. 3 beta-HSD activity was detected in in vitro matured oocytes (74.4 +/- 1.4%), 1-cell (72.9 +/- 6.1%), 2-cell (61.8 +/- 7.4%), 8-cell (50 +/- 5%), morulae (50.8 +/- 2.6%), blastocysts (94.4 +/- 3%), and hatched blastocysts (100 +/- 0%) meanwhile the 4-cell stage showed a significant reduction (16.7 +/- 4.7%). When total embryonic RNA of different stages was subjected to RT-PCR assays, the mRNA of 3 beta-HSD was found to be present in all developmental stages of in vitro produced bovine embryos, from the oocyte to the blastocyst, with a marked decrease at the 4-cell stage. To determine whether the temporal pattern of enzyme activity was dependent on the maternal to zygotic transition, embryos were incubated in the presence of a transcription inhibitor, alpha-amanitin. The reappearance of the enzyme activity after the 4-cell stage was blocked in alpha-amanitin treated embryos, indicating the requirement of embryonic transcription. On the other hand, the embryonic steroid metabolism was tested by incubating blastocyst with tritiated pregnenolone. Analysis of the metabolites by TLC indicated the production of a compound with a mobility identical to progesterone. These results described the expression of the 3 beta-HSD and the activity of this metabolic enzyme in bovine oocytes and preimplantation embryos, suggesting that steroids may act as autocrine effectors on preimplantation embryo development.
authors.affiliation: Instituto de Biología y Medicina Experimental, Consejo Nacional de Investigaciones Científicas y Técnicas, Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina.
authors.forename: M E
authors.initials: ME
authors.lastname: Chiappe
authors.forename: M L
authors.initials: ML
authors.lastname: Lattanzi
authors.forename: A A
authors.initials: AA
authors.lastname: Colman-Lerner
authors.forename: J L
authors.initials: JL
authors.lastname: Barañao
authors.forename: P
authors.initials: P
authors.lastname: Saragüeta
mesh_terms: D015096:3-Hydroxysteroid Dehydrogenases / Q000235:genetics / Q000378:metabolism*; D000546:Amanitins / Q000494:pharmacology; D000818:Animals; D001755:Blastocyst / Q000187:drug effects / Q000201:enzymology* / Q000502:physiology*; D002417:Cattle; D002478:Cells, Cultured; D003687:Dehydroepiandrosterone / Q000494:pharmacology; D005314:Embryonic and Fetal Development; D005260:Female; D005307:Fertilization in Vitro; D019384:Nucleic Acid Synthesis Inhibitors / Q000494:pharmacology; D009865:Oocytes / Q000502:physiology; D011247:Pregnancy; D011284:Pregnenolone / Q000378:metabolism; D011374:Progesterone / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism
chemical_list: D000546:Amanitins; D019384:Nucleic Acid Synthesis Inhibitors; D012333:RNA, Messenger; D003687:Dehydroepiandrosterone; D011374:Progesterone; D011284:Pregnenolone; D015096:3-Hydroxysteroid Dehydrogenases