Oestradiol-17 beta in the blood during seasonal reactivation of the diapausing blastocyst in a wild population of tammar wallabies.
Oestradiol-17 beta was measured by radioimmunoassay in cardiac blood from 143 pregnant and post-partum tammar wallabies shot in the wild during reactivation of the diapausing blastocyst, embryonic development, birth and post-partum oestrus. A transient rise in circulating oestradiol on 3 January coincided with or shortly preceded corpus luteum growth and blastocyst expansion; before 5 January mean corpus luteum weight was 14.3 +/- 0.44 mg (n = 65), while thereafter it exceeded 20 mg in two-thirds of the animals. Expanded blastocysts were first noted on 5 January. A second rise in the concentration of oestradiol in plasma, which occurred in late January, preceded parturition and coincided with follicular maturation; the mean (+/- S.E.M.) oestradiol concentration before 17 January was 27.9 +/- 1.10 pmol/1 (n = 110), whereas on or after this date it was 57.3 +/- 4.15 pmol/1 (n = 33). Thus oestradiol levels in peripheral plasma increased at parturition and postpartum oestrus, and showed a rise early in gestation which may be related to the termination of diapause.
D000828:Animal Population Groups / Q000097:blood*; D000818:Animals; D000835:Animals, Wild / Q000097:blood*; D010064:Embryo Implantation; D010065:Embryo Implantation, Delayed; D004958:Estradiol / Q000097:blood*; D004971:Estrus; D005260:Female; D007743:Labor, Obstetric; D007614:Macropodidae / Q000097:blood*; D008394:Marsupialia / Q000097:blood*; D049590:Postpartum Period; D011247:Pregnancy; D011863:Radioimmunoassay; D012621:Seasons
D004958:Estradiol