Change of Progesterone Level in the Uterine Venous Plasma of Pregnant Guinea-pigs and Progesterone Biosynthesis by the Placenta in Vitro

DOI Web Site

Bibliographic Information

Other Title
  • モルモットの妊娠期における子宮静脈血中のプロジェステロンと胎盤プロジェステロン合成能について
  • モルモット ノ ニンシンキ ニ オケル シキュウ ジョウミャク ケッチュウ ノ

Search this article

Abstract

Placental tissue slices of guinea-pigs were incubated in Krebs-Ringer phosphate buffer containing NAD and glucose using pregnenolone-4-14C as a substrate. The amount of progesterone converted from pregnenolone by the placenta at 50 days after mating was significantly larger than that of 64-65 days after mating (0.205 and O.159μg/100mg/hr., P<0.05). The 3β-hydmxysteroid dehydrogenase activity of the placenta seems to decrease at the last stage of pregnancy. Progesterone levels in the systemic and uterine venous plasma of the pregnant guinea-pigs were measured. There was no significant difference between them at the middle and late stages of pregnancy. This suggested that uterine venous plasma progesterone level was not affected by the placental progesterone. The progesterone levels in both systemic and uterine venous plasma were high in middle stage and low at the end of pregnancy, but rapid decrease of progesterone reflecting initiation of parturition, as seen in many other species, was not observed. In this species, the relationship between progesterone level and initiation of parturition is seemed to be specific, being complicated by the local effect of placental progesterone on the fetus or the uterus.

Journal

Details 詳細情報について

Report a problem

Back to top