Conservation of Australian Endangered Macropods
A project undertaken at the Institute of Reproduction and Development, Monash University, and supervised by IM Gunn
Many of Australia’s macropod species (kangaroos, wallabies etc.) are endangered. In order to ensure their conservation, it is essential to understand their reproductive biology, which differs from that of other mammals. This project investigated the reproductive biology of the eastern grey kangaroo and the red kangaroo. Although these species are not themselves endangered, they are closely related to other species that are under threat of extinction, and are therefore suitable models for study
A histological and ultrastructural study was made of the changes that occur during the formation of egg follicles within the ovaries of eastern grey and red kangaroos, from pouch young through to sexual maturity. Special attention was given to the occurrence and type of polyovular (multi-egg) follicles. The overall histological structure of the ovary was found to be similar in the two species, with the follicle population consisting mainly of monovular follicles, although polyovular follicles were found in pouch young and adult material.
Three types of polyovular follicles were observed in the adult eastern grey kangaroo, but polyovular follicles appeared to be less common in pouch young of this species. In the adult red kangaroo, polyovular follicles never contained more than two oocytes, while polyovular follicles in the adult eastern grey kangaroo frequently had more than two oocytes. Observations of progesterone receptor staining supported the hypothesis of an important role for progesterone at all stages of follicular development in both the eastern grey and red kangaroos.
The identity and distribution of the oestrogen receptor in the kangaroo ovary were examined with an immunohistochemical technique using a commercially-available polyclonal rabbit antibody directed against human oestrogen receptor.
This detailed study of the ovarian histology of the eastern grey and red kangaroos has identified similarities and differences not only between the two species, but also between sexually immature and mature individuals. In addition to investigating folliculogenesis at the histological level, this study has presented, for the first time, a detailed description of the oestrogen and progesterone receptors in eastern grey and red kangaroos.
Reinke, SN (2000). Ovarian structure and function in the eastern grey kangaroo (Macropus giganteus) and red kangaroo (Macropus rufus). MSc Thesis, Monash University.