Intrauterine development after diapause in the marsupial Macropus eugenii

Renfree, Marilyn B.; Tyndale-Biscoe, C. H.

doi:10.1016/0012-1606(73)90217-0

Cited by 145 publications

(115 citation statements)

References 16 publications

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“…Treatment of ovariectomized tammars with 1, 2 or 4 mg progesterone for 3 days reactivates most embryos, although most have degenerative changes (Berger & Sharman, 1969). Higher doses of 10 mg/day given over 10 days to intact tammars reactivates most embryos, but only about half of them develop normally, with the greatest incidence of abnormal development occurring before Day 11 after removal of pouch young (Renfree & Tyndale-Biscoe, 1973). Progesterone is therefore probably not the sole factor involved in embryo reactivation and maintenance of pregnancy, and the results of the present study suggest that oestradiol may be equally important.…”

Section: Discussionmentioning

confidence: 99%

“…Ovarian tissue was obtained from wild-shot seasonally reactivating tammars in 1983 and stored frozen. The stage of pregnancy was estimated from embryonic growth curves (Renfree & Tyndale-Biscoe, 1973) (Sokal & Rohlf, 1981).…”

Section: Methodsmentioning

confidence: 99%

“…By June, seasonal factors prevent reactivation until around the time of the summer solstice in December when it occurs over a 10-day period (Sharman, 1955;Berger, 1966; Tyndale-Biscoe, Hearn & Renfree, 1974). Diapausing embryos can be reactivated by progesterone injections, but about 10 mg/day is needed for about 10 days, and there is a 50% loss, mostly at early stages of development (Renfree & Tyndale-Biscoe, 1973). This suggests that progesterone may not act alone to induce normal reactivation.…”

Section: Introductionmentioning

confidence: 99%

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

Shaw¹,

Renfree²

1984

Reproduction

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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.

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Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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

Shaw¹,

Renfree²

1984

Reproduction

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“…There is a marked but transient peak of progesterone on Day 5 or Day 6 after removing the pouch young, which is followed by a return to basal concentrations by Day 9 and then a slow rise to maximum levels by Day 16 (Hinds & Tyndale-Biscoe, 1982a Not only is the progesterone production rate unusually high on Day 5 but the luteal cells undergo a transient hyperplasia then (Berger, 1970;Renfree & Tyndale-Biscoe, 1973) (Sharman & Berger, 1969 ;Tyndale-Biscoe, 1970 (Sernia et al, 1980). We conclude that prolactin has no significant role after the CL has reactivated.…”

Section: Discussionmentioning

confidence: 99%

“…During lactation this suppression appears to be mediated by secretion of prolactin from the pituitary (Tyndale-Biscoe & Hawkins, 1977) but reactivation can be induced experimentally by removal of the sucking pouch young (Renfree & Tyndale-Biscoe, 1973), denervation of the active mammary gland (Renfree, 1979), injection of bromocriptine (Tyndale-Biscoe & Hinds, 1981) or hypophysectomy (Hearn 1974; Tyndale-Biscoe & Hawkins, 1977). When reactivation occurs the corpus luteum increases in size from 10 to about 60 mg (Renfree, Green & Young, 1979) and circulating progesterone rises from < 200 to about 600 pg/ml (Lemon, 1972;Hinds & Tyndale-Biscoe, 1982a).…”

Section: Introductionmentioning

confidence: 99%

In-vitro secretion of progesterone by the corpus luteum of the tammar wallaby, Macropus eugenii

Hinds¹,

Evans²,

Tyndale-Biscoe³

1983

Reproduction

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Summary. Luteal tissue collected from tammars 0, 5, 9 and 16 days after removal of pouch young actively produced progesterone in vitro. On Days 5, 9 and 16 luteal progesterone concentration was not significantly different from Day 0 (quiescence).However, the net production of progesterone was significantly higher on Day 5 (P < 0\m=.\05) than at any other stage, and we suggest that the corpus luteum is the main source of the rise in progesterone in the peripheral circulation at Days 5\p=n-\8of the delayed or non-delayed cycle.Addition of ovine prolactin to corpora lutea incubated on Day 5 after removal of pouch young had no effect on luteal progesterone concentration or the production of progesterone. We therefore conclude that the tonic inhibition exerted by prolactin on the corpus luteum does not affect the steroidogenic capacity of the luteal tissue but may inhibit luteal cell growth during quiescence.

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Mouse embryos used as a bioassay to determine control of marsupial embryonic diapause

Spindler

Renfree

1999

J. Exp. Zool.

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Intrauterine development after diapause in the marsupial Macropus eugenii

Cited by 145 publications

References 16 publications

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

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

In-vitro secretion of progesterone by the corpus luteum of the tammar wallaby, Macropus eugenii

Mouse embryos used as a bioassay to determine control of marsupial embryonic diapause

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