Studies on amphibian yolk: VIII. The estrogen-induced hepatic synthesis of a serum lipophosphoprotein and its selective uptake by the ovary and transformation into yolk platelet proteins in Xenopus laevis☆☆☆

[摘要] 14C-labeledleucineinjectedintoXenopusrapidlybecomesincorporatedintoliverprotein;subsequentlythespecificactivityofserumproteinrises.Theextentofserumproteinlabelingispronounced,particularlyinestrogen-treatedmalesandvitellogenicfemales;however,inthelattercase,labeledproteinrapidlydisappearsfromthecirculationandthespecificactivityofovarianproteinsimultaneouslyrisestoaplateau.Serumchromatogramsdemonstratethatmostofthevariablelabelingoftheserumisthefunctionofasingleserumcomponent,designatedSLPP.Thiscomponentisproducedbytheliverasindicatedbythesyntheticcapacityofliverslicesinvitro,andthehepaticsynthesisandsecretionofSLPPappearstobeunderthecontrolofestrogen.SLPPistakenupselectivelybythematuringovaryandspecificallybythevitellogenicoocyte.Thelatter,however,mustfirstbeactivatedbyahormonalfactorinordertoperformthistask.Onceincorporatedintotheoocyte,SLPPappearstotransformintothetwoproteinsofthecrystallineyolkplatelet,phosvitinandlipovitellin,andhencerepresentstheprecursormoleculeforcrystallineyolk.

[学科分类] 生物科学（综合）

[关键词] HCG;human chorionic gonadotropin;SLPP;serum lipophosphoprotein;TCA;trichloroacetic acid