Milligan S R, Finn C A
Physiology, Biomedical Sciences Division, King's College, Strand, London, UK.
Hum Reprod. 1997 Mar;12(3):602-7. doi: 10.1093/humrep/12.3.602.
A study of the degree of progesterone support required for the maintenance of various stages of pregnancy was undertaken in mice. Mated females were ovariectomized at various stages of pregnancy and progesterone and oestradiol support provided by s.c. Silastic implants with known release characteristics. In the earliest stages of pregnancy (days 1-5), very low concentrations of progesterone (<25% of normal physiological values) were sufficient to maintain pre-implantation stages and allow implantation. In the immediate post-implantation period (days 5-9), the development of implantation sites and decidualization required considerably higher progesterone support. In mid-pregnancy (days 11-14), progesterone alone could not maintain pregnancy unless present in very high amounts; however, the presence of oestradiol during this period lowered the progesterone requirements to well within the physiological range. This effect of oestradiol started on day 11 but required the level of oestradiol support to be kept within strictly defined limits, with high concentrations inducing abortion. Progesterone alone was able to maintain pregnancy from day 15. These results indicate that the minimal progesterone support required for pregnancy in mice varies considerably at different stages of pregnancy and is at least partly modulated by oestradiol.
在小鼠身上进行了一项关于维持妊娠各阶段所需孕酮支持程度的研究。已交配的雌性小鼠在妊娠的不同阶段接受卵巢切除术，并通过具有已知释放特性的皮下硅橡胶植入物提供孕酮和雌二醇支持。在妊娠的最早阶段（第1 - 5天），极低浓度的孕酮（<正常生理值的25%）足以维持植入前阶段并允许着床。在着床后立即阶段（第5 - 9天），着床部位的发育和蜕膜化需要相当高的孕酮支持。在妊娠中期（第11 - 14天），除非孕酮含量非常高，否则单独的孕酮无法维持妊娠；然而，在此期间雌二醇的存在将孕酮需求降低到了生理范围内。雌二醇的这种作用从第11天开始，但要求雌二醇支持水平保持在严格定义的范围内，高浓度会导致流产。单独的孕酮从第15天起能够维持妊娠。这些结果表明，小鼠妊娠所需的最低孕酮支持在妊娠的不同阶段有很大差异，并且至少部分受雌二醇调节。
