Δ5-3β-Hydroxysteroid dehydrogenase and estradiol-17β-hydroxysteroid dehydrogenase activity in preimplantation hamster embryos☆

[摘要] Preimplantationgoldenhamster(Mesocricetusauratus)embryoswererecoveredondays1(=dayoffindingspermatozoainthevagina)through4ofpregnancy.Postimplantationembryoswerestudiedinsectionedgestationsacsexcisedondays5and6.Δ5-3β-Hydroxysteroiddehydrogenase(3β-HSD)activityinembryoswasdeterminedhistochemically.Therewasnoenzymeactivityondays1and2.Weakactivitywasfirstobservedat08:00–09:00hronday3,theactivitythenincreased,peakedat01:00–03:00hronday4,considerablydeclinedby08:00–09:00hr(day4),andwasabsentondays5and6.Theseresultssuggestthatthepreimplantationembryossynthesizesteroidhormones.Itwaspreviouslyhypothesized(DickmannandDey,1973,1974)that,hormonessynthesizedbythepreimplantationratembryoparticipateintheregulationofmorulatoblastocysttransformationandimplantationoftheblastocyst.Thishypothesisisapplicabletothehamster.Inadditionto3βHSD,estradiol-17β-hydroxysteroiddehydrogenaseactivitywasobservedinday3embryos,suggestingthattheembryosynthesizesestrogen.

[学科分类] 生物科学（综合）