Harder J D, Fleming M W
Science. 1981 Jun 19;212(4501):1400-2. doi: 10.1126/science.7233228.
Concentrations of estradiol and progesterone in blood collected during the 12.5-day gestation period of the Virginia opossum were not significantly different from those during equivalent days of the estrous cycle. Progesterone was correlated with an index of corpora luteral mass. Ratio of estradiol to progesterone were highest 3 to 4 days before estrus and on the day of parturition.
在弗吉尼亚负鼠12.5天的妊娠期内采集的血液中，雌二醇和孕酮的浓度与发情周期相同天数时的浓度无显著差异。孕酮与黄体质量指数相关。雌二醇与孕酮的比值在发情前3至4天和分娩当天最高。
