The biosynthesis of progesterone by cultured mouse midgestation trophoblast cells
[摘要] Theabilityofculturedmidgestationmousetrophoblastcellstosynthesizeprogesteronefrompregnenolonehasbeenmonitoredbyradioimmunoassayorchromatographyandcrystallization.Theconversionofpregnenolonetoprogesteroneisalmostcompletelyblockedbycyanoketone,aknowninhibitorofΔ5,3β-hydroxysteroiddehydrogenase(3β-HSD)activity.Sincethereislittleornofurthermetabolismoftheprogesteroneformed,theabilityoftrophoblastcellstoconvertpregnenolonetoprogesteroneinvitroisanaccuratereflectionoftheactivityof3β-HSDinthesecells.Midgestationculturesofgianttrophoblastcellshaveasubstantiallyhigher3β-HSDspecificactivitythanthesmallerectoplacentalconecells.Neithergianttrophoblastnorectoplacentalconecellculturesshowanincreased3β-HSDspecificactivityinresponsetoavarietyofhormones,includinggonadotrophins.Infact,regardlessofthegestationageatwhichthetrophoblastculturesareinitiated,3β-HSDactivityinevitablyfollowsthesametemporalpatternobservedinvivo.Takentogether,thesefactssuggestthatthelevelsof3β-HSDintrophoblastcellsareintrinsicallycontrolledandthat,unliketheovary,progesteroneproductionbytrophoblastcellsinvivoisnotinfluencedbygonadotrophichormonelevels.
[发布日期] [发布机构]
[效力级别] [学科分类] 生物科学（综合）
[关键词] [时效性]
