The Concentration of Unconjugated Oestrone, Oestradiol-17  and Oestradiol-17  in the Maternal Plasma of the Pregnant Ewe in Relation to the Initiation of Parturition and Lactation

Abstract

The concentration of unconjugated oestrone, oestradiol-17a and oestradiol-17/? has been measured in the maternal jugular venous plasma of pregnant sheep every 6 hr over the period 108 hr before to 72 hr after parturition. Measurable levels of each oestrogen were present 108 hr before parturition and by about 40 hr, the concentration began to increase markedly. Levels of 200 to 350 pg/ml for oestrone and 100 to 150 pg/ml for oestradiol-17a and for oestradiol-17/? were found just before parturition. At 12 hr after parturition, the concentration of oestrone and oestradiol-17ß had fallen to < 15 pg/ml. Levels ofoestradiol17a remained elevated for a longer period after parturition and did not fall to <35 pg/ml until 48 to 60 hr after parturition.

Progesterone and oestrogen concentrations in plasma of Barbary sheep (aoudad, Ammotragus lervia) compared with those of domestic sheep and goats during pregnancy

“…Both oestradiol and oestrone sulphate showed a doubling in concentration 24 h before delivery which is in agreement with the findings of others (sheep: Challis, 1971; Robertson & Smeaton, 1973;Tsang, 1978;Rawlings & Ward, 1978a;goat: Challis & Linzell, 1971;Rawlings & Ward, 1978b;Thorburn et ai, 1972).…”

Changes in the Concentration of Unconjugated Oestrone, Oestradiol-17 and Oestradiol-17 in the Maternal Plasma of the Pregnant Cow in Relation to the Initiation of Parturition and Lactation

“…concentration increased by a further 150 pg/ml (50%) while the oestradiol-17a reached a plateau and indeed appeared to fall slightly. After (Challis, 1971;Thorburn, Nicol, Bassett, Shutt & Cox, 1972;Robertson & Smeaton, 1973) and in the goat (Challis & Linzell, 1971 ;Thorburn et al, 1972). However, it should be noted that, because blood samples were taken only once per day at a fixed time, a wide variation in time could exist between the time of the last sample and the time of parturition which could have modified the values obtained for the last two samples before parturition.…”

Uterine and Placental Growth: RNA and Protein Metabolism and Steroid Hormone Receptor Levels in the Endometrium, Whole Uterus and Cotyledons during Pregnancy in the Ewe

“…The capacity of the uterus to grow and differentiate in response to circulating ovarian steroid hormones may be determined, in part, by the level of high-affinity E2 and P receptors in uterine cytoplasm (see Clark and Peck 1979 for a review). Except during the first and last 4-7 days of pregnancy, gestation in the ewe is characterized by (1) maternal peripheral serum P levels which are not less than those seen during the luteal phase of the oestrous cycle and which between days 50 and 120 increase to levels 2-5 times those seen during the luteal phase of the cycle; and (2) extremely low maternal peripheral serum levels of unconjugated oestrogens (Bassett et al 1969;Charnley et al 1973; Robertson and Smeaton 1973;Tsang 1978).…”