scholarly journals Effects of corpus luteum removal on progesterone, oestradiol-17  and LH in early pregnancy of the tammar wallaby, Macropus eugenii

Reproduction ◽  
1988 ◽  
Vol 83 (1) ◽  
pp. 185-191 ◽  
Author(s):  
T. P. Fletcher ◽  
M. B. Renfree
Keyword(s):  
Corpus Luteum ◽  
Early Pregnancy ◽  
Tammar Wallaby ◽  
Macropus Eugenii

scholarly journals Growth of the corpus luteum and its progesterone content during pregnancy in the tammar wallaby, Macropus eugenii

Reproduction ◽  
1979 ◽  
Vol 57 (1) ◽  
pp. 131-136 ◽  
Author(s):  
M. B. Renfree ◽  
S. W. Green ◽  
I. R. Young
Keyword(s):  
Corpus Luteum ◽  
Tammar Wallaby ◽  
Macropus Eugenii

PROLACTIN RECEPTORS IN THE MAMMARY GLAND, CORPUS LUTEUM AND OTHER TISSUES OF THE TAMMAR WALLABY, MACROPUS EUGENII

1979 ◽  
Vol 83 (1) ◽  
pp. 79-89 ◽  
Author(s):  
C. SERNIA ◽  
C. H. TYNDALE-BISCOE
Keyword(s):  
Mammary Gland ◽  
Corpus Luteum ◽  
Specific Binding ◽  
Tammar Wallaby ◽  
Binding Activity ◽  
Breeding Cycle ◽  
Macropus Eugenii ◽  
Lactating Mammary Gland ◽  
The Mean ◽  
Ovine Prolactin

SUMMARY Specific binding of radio-iodinated ovine prolactin to subcellular tissue fractions of the tammar wallaby (Macropus eugenii) was investigated. Specific binding was found, in order of decreasing binding activity, in the lactating mammary gland, corpus luteum, corpus albicans, adrenal gland and ovary. Specific binding was absent in kidney, liver, brain and inactive mammary gland. The mean association constant (Ka at 23 °C) was determined as 0·90 × 109, 2·20 × 109, 2·44 × 109, 3·38 × 109 and 10·98 × 1091/mol for mammary gland, adrenal, corpus albicans, corpus luteum and ovary respectively. The mean receptor concentration (N) varied from 92·87 × 10−14 mol/mg protein for the mammary gland to 1·03 × 10−14 mol/mg protein for the ovary. The concentration in the corpus luteum varied between tissue pools collected at different times of the annual breeding cycle. The specificity for prolactin was shown in the mammary gland and corpus luteum by the failure of ovine FSH, LH, GH and TSH to displace 125I-labelled ovine prolactin, whereas it was displaced readily by both ovine and bovine prolactin.

Daily prolactin pulse inhibits the corpus luteum during lactational quiescence in the marsupial, Macropus eugenii

2013 ◽  
Vol 25 (2) ◽  
pp. 456 ◽  
Author(s):  
L. A. Hinds ◽  
C. H. Tyndale-Biscoe
Keyword(s):  
Corpus Luteum ◽  
Tammar Wallaby ◽  
Marked Contrast ◽  
Previous Conclusion ◽  
Macropus Eugenii ◽  
Rate Limiting Step ◽  
Limiting Step ◽  
Progesterone Synthesis ◽  
Rate Limiting

The corpus luteum (CL) of the tammar wallaby is inhibited by prolactin during lactation and seasonal quiescence. In seasonal quiescence a daily transient pulse of prolactin (PRL) of less than 2 h duration is sufficient to maintain inhibition. We investigated whether the same inhibition applies in lactation and, if so, how. Our results show that inhibition of the CL during lactation is maintained by a transient pulse of prolactin once a day. They also show that the minimum time without a PRL pulse for the CL to escape inhibition is more than 48 h and less than 72 h. Nevertheless, some animals had a longer refractory period than 72 h, which was reflected in a longer interval to the progesterone peak and birth. These results support the previous conclusion that PRL exercises its effect on a rate-limiting step in progesterone synthesis and secretion rate from the CL, which precedes any increase in its mass. Therefore, we conclude that the role of PRL is to act as a luteostatic agent, an effect that is in marked contrast to its luteotrophic effect in many eutherian species, including rodents.

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

Reproduction ◽  
1983 ◽  
Vol 67 (1) ◽  
pp. 57-63 ◽  
Author(s):  
L. A. Hinds ◽  
S. M. Evans ◽  
C. H. Tyndale-Biscoe
Keyword(s):  
Corpus Luteum ◽  
Tammar Wallaby ◽  
Macropus Eugenii

scholarly journals Uterine morphology during diapause and early pregnancy in the tammar wallaby (Macropus eugenii )

2016 ◽  
Vol 229 (3) ◽  
pp. 459-472 ◽  
Author(s):  
Melanie K. Laird ◽  
Cyrma M. Hearn ◽  
Geoff Shaw ◽  
Marilyn B. Renfree
Keyword(s):  
Early Pregnancy ◽  
Tammar Wallaby ◽  
Macropus Eugenii

Effects of the ovary, sucking stimulus and season on the pattern of LH and FSH release in the female tammar, Macropus eugenii

1992 ◽  
Vol 4 (1) ◽  
pp. 25 ◽  
Author(s):  
LA Hinds ◽  
PJ Diggle ◽  
CH Tyndale-Biscoe
Keyword(s):  
Corpus Luteum ◽  
Breeding Season ◽  
Ovarian Tissue ◽  
Plasma Concentrations ◽  
Low Frequency ◽  
Tammar Wallaby ◽  
Pulse Frequency ◽  
Sequential Effects ◽  
Macropus Eugenii ◽  
Bilateral Ovariectomy

The sequential effects of removal of the corpus luteum, removal of the non-luteal ovary and sucking stimulus and the effects of season of the year on the release of luteinizing hormone (LH) and follicle stimulating hormone (FSH) have been determined in the tammar wallaby, Macropus eugenii. Plasma concentrations of LH and FSH were measured at 15 min intervals for 6 h in eight animals at four successive times in the breeding season (lactational quiescence); (A) while they were intact and lactating, (B) 10 days after removal of the ovary bearing the quiescent corpus luteum, (C) 21 days after bilateral ovariectomy and (D) 21 days after removal of the sucking stimulus, and (E) in the following non-breeding season (seasonal quiescence). Single blood samples were taken twice weekly during lactational quiescence. In the presence of ovarian tissue, basal concentrations of LH were low (0.94 ng mL-1) with pulses of low magnitude (1.3 ng mL-1) and low frequency (1.4 pulses per 6 h). There was no response to luteectomy but all three parameters increased after bilateral ovariectomy. Removal of the sucking stimulus affected the LH pulse frequency but seasonal differences were not evident. The pattern of release of FSH was not pulsatile. There was no response to luteectomy in basal concentrations of FSH but these rose significantly after bilateral ovariectomy (P less than 0.001) in lactational quiescence. There was no effect of removing the sucking stimulus but in seasonal quiescence concentrations were higher. The results indicate that non-luteal ovarian tissue is essential for the negative-feedback effects on LH and FSH secretion, that the pattern of release of LH, but not FSH, is pulsatile, and that there is no marked seasonal change in hypothalamo-hypophysial activity.

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