Downing S J, Sherwood O D
Endocrinology. 1985 Mar;116(3):1200-5. doi: 10.1210/endo-116-3-1200.
Length of gestation, duration of labor and delivery, and fetal survival were determined in control intact pregnant rats (group C). Pregnant rats were bilaterally ovariectomized on day 9 and given progesterone (P) implants and, in addition, one of the following injection regimens; estrogen (E; group OPE), E and porcine relaxin (R; group OPER), or porcine R (group OPR). Hormone treatments were given in doses designed to produce serum levels of these hormones similar to those observed in intact pregnant rats. The P implants were removed during the evening of day 21 to mimic the decline in serum P levels that normally occurs as a result of luteolysis. Animals in groups OPE and OPR exhibited significantly prolonged gestation, prolonged duration of labor and delivery, and reduced fetal survival compared with controls. Group OPER animals exhibited slightly but not significantly shorter length of gestation, similar duration of labor and delivery, and similar rate of fetal survival compared to control values. Group OPER animals showed normal maternal behavior and were able to suckle their young.
测定了对照未切除卵巢的妊娠大鼠（C组）的妊娠期长度、分娩持续时间以及胎儿存活率。妊娠大鼠在第9天进行双侧卵巢切除术，并植入孕酮（P），此外，给予以下注射方案之一：雌激素（E；OPE组）、E和猪松弛素（R；OPER组）或猪R（OPR组）。激素治疗的剂量设计为使这些激素的血清水平与未切除卵巢的妊娠大鼠中观察到的水平相似。在第21天晚上取出P植入物，以模拟由于黄体溶解通常发生的血清P水平下降。与对照组相比，OPE组和OPR组的动物妊娠期显著延长、分娩持续时间延长且胎儿存活率降低。与对照值相比，OPER组动物的妊娠期略短但无显著差异，分娩持续时间相似，胎儿存活率相似。OPER组动物表现出正常的母性行为，能够哺育幼崽。
