Oestradiol in follicular fluid and in utero-ovarian venous and peripheral plasma during parturition and post-partum oestrus in the tammar, Macropus eugenii

Abstract

Oestradiol-17 beta was measured in plasma and follicular fluid by a radioimmunoassay validated for the tammar. Plasma was sampled from the peripheral circulation and both utero-ovarian veins to assess the contribution of oestradiol from the corpus luteum in one ovary and from the Graafian follicle in the other during late pregnancy, parturition, post-partum oestrus and ovulation. Concentrations of oestradiol in the peripheral plasma and in the vein draining the CL remained less than 5 pg/ml on all days except the day of parturition, when they were 12.7 pg/ml and 14.3 pg/ml respectively. Mean oestradiol concentration in the vein draining the Graafian follicle was significantly higher than the mean peripheral concentration on Days 24-27. The highest average concentration (36.5 pg/ml) occurred on Day 27 coincident with parturition and before oestrus. These latter concentrations were significantly correlated with the concentration and total oestradiol in the fluid of the preovulatory Graafian follicle (r = 0.73 and r = 0.82 respectively), thus providing strong evidence that the Graafian follicle is the main source of oestradiol in the peripheral circulation at this time.

Effects of removal in late pregnancy of the corpus luteum, Graafian follicle or ovaries on plasma progesterone, oestradiol, LH, parturition and post-partum oestrus in the tammar wallaby, Macropus eugenii

“…3 support the conclusion of Harder et al (1984) that the large Graafian follicle is the primary source of oestradiol in the peripartum tammar, because removal of the ovary with the Graafian follicle eliminated the post-partum rise in oestradiol. Basal concentrations of oestradiol in the plasma of animals in Groups F-2 and F-3 were apparently maintained by secretion of oestradiol from growing follicles in the remaining ovary, because oestradiol was generally undetectable in the bilaterally ovariectomized tammars.…”

“…Hormone concentrations were determined by radioimmunoassays previously validated for tammar plasma. Oestradiol-17ß was measured by the method described by Harder et al (1984), using antiserum (lot 6181) provided by Dr R. I. Cox, CSIRO, Sydney. The assay sensi¬ tivity was 2-5 pg/ml plasma and intra-and interassay coefficients of variation were 3% and 15%, respectively.…”

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

“…In the present study, quiescent blastocysts reactivated and resulted in successful birth in at least five control animals. The proportion of control animals that apparently did not have blastocysts (25 or 37.5%) was similar to previously reported figs of 17% for wild animals (Renfree & TyndaleBiscoe 1973) and 23% for captive animals (Harder et al 1984). In contrast to the results for control animals, successful blastocyst reactivation and birth appeared to occur in only one treated animal.…”

Intra-cytoplasmic sperm injection in a marsupial

“…In the wild, tammars normally only produce one young a year (Tyndale-Biscoe & Renfree 1987). Ovulation is spontaneous and occurs about 40 h after mating and about 24 h after the luteinizing hormone surge that is triggered by a rise in oestradiol produced by the Graafian follicle (Harder et al 1984, Shaw & Renfree 1984, Tyndale-Biscoe & Renfree 1987, Renfree & Lewis 1996. As in all marsupials, fertilization occurs in the upper oviduct, the oocyte moves through the oviduct within 24 h and cleavage occurs in the uterus (Renfree & Lewis 1996).…”