Influence of progesterone and oestradiol-17β on blastocysts of the tammar wallaby (Macropus eugenii) during seasonal diapause

Abstract

Forty tammar wallabies, presumed to be carrying quiescent blastocysts, were injected with progesterone and oestradiol alone, or in combination, during seasonal quiescence when the corpus luteum is inactive. Plasma progesterone concentrations were increased to values equivalent to those of late pregnancy for the duration of the treatment in progesterone-treated groups but otherwise remained at values equivalent to seasonal quiescence. Tammars treated with low doses of oestradiol showed no measurable increase in plasma oestradiol concentrations but in those treated with high doses plasma concentrations were increased to oestrous levels. At autopsy on Day 18 after the start of treatment the emb..