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Australian Journal of Zoology Australian Journal of Zoology Society
Evolutionary, molecular and comparative zoology
RESEARCH ARTICLE

Early pregnancy factor in marsupials

Y. P. Cruz A D , H. Morton B , A. C. Cavanagh B , L. Selwood C , S. D. Wilson A and M. Sasaki A
+ Author Affiliations
- Author Affiliations

A Department of Biology, Oberlin College, Oberlin, OH 44074, USA.

B School of Medicine, University of Queensland, Brisbane, Qld 4029, Australia.

C Department of Zoology, University of Melbourne, Parkville, Vic. 3010, Australia.

D Corresponding author. Email: yolanda.p.cruz@oberlin.edu

Australian Journal of Zoology 54(3) 211-215 https://doi.org/10.1071/ZO05050
Submitted: 31 August 2005  Accepted: 8 March 2006   Published: 22 June 2006

Abstract

Maternal recognition of pregnancy in marsupials occurs in more subtle ways than it does in eutherians. For instance, unlike in eutherians, the plasma progesterone profiles of pregnant and non-pregnant animals are similar during the luteal phase. It is typically during the brief luteal phase that both gestation and parturition occur in marsupials. Yet histological and physiological changes have been documented between gravid and non-gravid uteri in certain monovular marsupials and between pregnant and non-pregnant animals in polyovular marsupials. Early pregnancy factor (EPF), a 10.8-kDa serum protein known to be homologous to chaperonin 10, is associated with maternal immunosuppression, embryonic development and pregnancy in eutherian mammals. It has been reported in two Australian marsupials: the dasyurid Sminthopsis macroura and the phalangerid Trichosurus vulpecula. This paper documents its occurrence in the New World didelphid Monodelphis domestica. EPF is detectable by rosette inhibition assay in the peripheral circulation of pregnant but not of non-pregnant or pseudopregnant animals. Our work focuses on the embryo–maternal signalling role of EPF during pregnancy. Because progesterone-driven changes are similar in pregnant and non-pregnant marsupials, these animals are an excellent laboratory model in which to investigate the role of EPF in orchestrating the physiological changes necessary to sustain pregnancy.


Acknowledgment

YPC was funded by research grants from Oberlin College. She acknowledges with gratitude the technical assistance of Jasmine McCammon and Twila Conley. The use of M. domestica in this study was approved by the Institutional Animal Care and Use Committee of Oberlin College.


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