Physiological changes in the bloodstream of chick embryos exposed to teratogenic doses of hypoxia

[摘要] Exposureof5-daychickembryostomoderatehypoxia(10.5%for5hours)precipitatesmalformations.Mostdefectsarecausedbythe“edemasyndrome,”markedinitiallybyasignificantincreaseinallbodyfluids.Acomprehensiveanalysisofthebloodserumofnormalandtreatedchickswasmade,usingavarietyofmicrochemicaltechniques.Intheserumfromhypoxia-treatedembryos,lacticacid,freeaminoacids,potassium,andcarbondioxideincrease;sodium,calcium,chloride,andglucosedecrease;proteinandinorganicphosphateremainconstant.Exposuretohypoxiacausesradicalchangesinthecompositionoftheserum.Nevertheless,thepHandosmoticpressureremainunchanged.Theexistenceofstrongdifferencesinsodium,potassium,andwaterconcentrationbetweenthebloodstreamandthefluidswhichsurroundtheextraembryoniccapillariesisinterpretedasanindicationofsignificantregulatoryactivitybysomeembryonicorextraembryonicorgan,perhapstheyolksac.Changesintheconcentrationofthesefactorsinthebloodstreamafterexposuretohypoxiaarebestexplainedastheresultofinterferencewithosmoregulatoryactivity.Moderatehypoxiaproducesfluidandelectrolytedisturbancesinthechickembryowhicheventuallyleadtothedevelopmentofmalformations.Aconsiderationofaspectsofthefluidphysiologyoftheembryoishelpfulinunderstandingthemechanismofteratogenicactionofhypoxia.

[学科分类] 生物科学（综合）