ウシ胎盤におけるプロゲステロンとエストロゲンの生合成

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  • 稲葉 俊夫
    大阪府立大学農学部家畜外科学教室
  • 岡 章生
    大阪府立大学農学部家畜外科学教室
  • 纐纈 雄三
    大阪府立大学農学部家畜外科学教室 日本農産工業株式会社
  • 中間 実徳
    大阪府立大学農学部家畜外科学教室 山口大学農学部
  • 藺守 龍雄
    大阪府立大学農学部家畜外科学教室

書誌事項

タイトル別名
  • Progesterone and estrogen synthesis by the bovine Placenta.

抄録

To assess the possible source of estrogens in the cow during perinatal period, the authors measured estrogen contents, secretion rate of estrogens and progesterone by the method of in vitro perifusion, and progesterone metabolites using [14C]-progesterone in the placental tissue.<BR>Estrone, estradiol-17α and -17β in the bovine placentae were detected by gas liquid chromatography. Total estrogen quantities present were about 10μg/1kg of tissue at 5 months of pregnancy. They increased during pregnancy, and reached to about 55μg/1kg of tissue at 9 months of pregnancy. <BR>Fetal placental cells were prepared using collagenase in a Eagle MEM medium. Estrogens and progesterone secreted by dispersed cells were determined by radioimmunoassay during 3 to 5 hours of perifusion. Fetal placental cells at 6.5 months of pregnancy and term produced higher estrogens in the effluent media, while those at 7.5-8 months of pregnancy and term produced higher progesterone.<BR>Each 100mg of fetal placental tissue was incubated with [4-14C]-progesterone (0.2μCi/3.6nmol) and NADPH. Radioactive metabolites were then separated by thin layer chromatographies and identified with the method of derivative formation and recrystallization to a constant specific activity. Placenta after 7 months of gestation converted significant amounts (up to 33%) of progesterone to 20-hydroxy-progesterone. However, no estrogens were shown to be formed in all fetal placental tissues examined. Thus, it appears unlikely that estrogens secreted by fetal placental tissue during perinatal period are synthesized from progesterone, but it could be synthesized from other steroid substrate, such as pregnenolone.

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