Development of gluconeogenic enzymes in fetal sheep liver and kidney

[摘要] Inthesheep,thesystemofenzymesnecessaryforconversionofnonhexosesubstratestoglucosebecomesactiveduringlatefetallife.Glucose-6-phosphataseandfructose-1,6-diphosphatase,twoofthefourkeygluconeogenicenzymes,appearinsignificantamountsbetween100and120daysgestation.Phosphoenolpyruvatecarboxykinaseactivityiscomparabletomatureanimalsasearlyas45daysgestation.Twoaminotransferases,necessarytoallowaminoacidaccesstothegluconeogenicpathway,likewisehavesubstantialactivityasearlyas45daysgestation.Hence,thesurgeofglucose-6-phosphataseandfructose-1,6-diphosphataseat100–120daysgestationmakespossibletheendogenousproductionofnewglucosebyfetalsheepatatimewhentheamountofglucosetransferredfromthematernalcirculationislessthanthetotalaerobicsubstrateutilizedbythefetus.Bothrenalcortexandliverhavesimilardevelopmentalpatternsforthegluconeogenicenzymes,althoughrenalcortexgenerallyshowsgreateractivitythanliver.Thisobservationholdstruefortissuefrombothfetalandmatureanimals.

[学科分类] 生物科学（综合）