Concentrations of oestradiol-17  in plasma and corpora lutea throughout pregnancy in the tammar, Macropus eugenii

Abstract

Summary. Oestradiol-17\g=b\ concentrations were measured by radioimmunoassay in peripheral blood samples from 10 tammar wallabies after their pouch young were removed to terminate embryonic diapause. Oestradiol concentrations rose from 8\m=.\3\m=+-\1\m=.\2 pg/ml on Days 3 and 4 to a peak of 15\m=.\8\m=+-\2\m=.\9 pg/ml on Day 5, coincident with an increase in 'progesterone' concentrations, and then fell to 10\m=.\5 \m=+-\ 2\m=.\7 pg/ml on Day 7. No changes in oestradiol concentrations were associated with parturition. Five females came into oestrus and mated 9\m=.\8 \ m=+-\ 6\m=.\1h post partum; peak concentrations of plasma oestradiol (20\m=.\9\ m=+-\ 2\m=.\1 pg/ml) occurred around the time of mating. None of the females that did not mate up to the end of the experiment at Day 30 had a rise in plasma oestradiol concentrations. Corpora lutea contained 20-100 pg oestradiol during pregnancy. The highest ovarian oestradiol content (> 1200 pg) was measured in whole ovaries containing Graafian follicles from full-term pregnant females. The rise in oestradiol concentrations at Day 5 may be important in the termination of diapause. The post-partum increase in plasma oestradiol concentrations coincides with oestrus.

Uterine and embryonic metabolism after diapause in the tammar wallaby, Macropus eugenii

“…At Day 5 after removal of young there is a surge of progesterone secretion by the corpus luteum (Hinds, Evans & Tyndale-Biscoe, 1983) and peripheral plasma progesterone concentrations rise to a transient peak of about 450 pg/ml between Days 5 and 8 (Hinds & Tyndale-Biscoe, 1982). Similarly, plasma oestradiol-17ß concentrations rise from 8-3 + 1-2 pg/ml on Days 3 and 4 to a peak of 15-8 + 2-9 pg/ml on Day 5, coincident with the progesterone peak, and fall to 10-5 + 2-7 pg/ml on Day 7 (Shaw & Renfree, 1984). From Day 10 progesterone concentrations rise again to a plateau of about 500-800 pg/ml then fall precipitously around the time of parturition (Tyndale-Biscoe, Hinds, Horn & Jenkin, 1983;Shaw & Renfree, 1984).…”

Effects of oestradiol-17 on peripheral plasma concentrations of LH and FSH in ovariectomized tammars (Macropus eugenii)

“…In Exp. 1 these doses produced maximum depression down to similar values (1-8 ng/ml) at 6, 12 and 24 h respectively after injection (Table 1 In both groups of animals the response to the highest dose of oestradiol gave an LH concentration in the peripheral circulation that was transiently raised to a level similar to that observed in intact females at oestrus (Flint & Renfree, 1982;Shaw & Renfree, 1984). The secondary rise in LH, induced within 12-18 h of this peak in oestradiol, was very similar in both magnitude and timing to the preovulatory LH surge in intact females.…”

“…Oestradiol concentrations in peripheral plasma are generally very low or undetectable during seasonal quiescence (< 10 pg/ml) (Flint & Renfree, 1982) and during pregnancy and the oestrous cycle (Shaw & Renfree, 1984). A transient peak (16 pg/ml) occurs early in these cycles with significant increases around the time of mating (21 pg/ml) (Shaw & Renfree, 1984) and oestrus (12-7 pg/ml) (Harder, Hinds, Horn & Tyndale-Biscoe, 1984). …”

Long-term effects of deslorelin implants on reproduction in the female tammar wallaby (Macropus eugenii)

“…Hormonal profiles during pregnancy and the oestrous cycle have been well characterised in the tammar wallaby (Hinds & Tyndale-Biscoe 1982, Tyndale-Biscoe et al 1983, Shaw & Renfree 1984. Basal progesterone concentrations during lactation and the first 5 days of the cycle are approximately 200 pg/ml.…”