Jenkin G, Jorgensen G, Thorburn G D, Buster J E, Nathanielsz P W
Can J Physiol Pharmacol. 1985 May;63(5):500-8. doi: 10.1139/y85-086.
Premature induction of delivery in fetuses infused with graded doses of cortisol was brought about in 123.5 +/- 7.7 h (mean +/- SEM, n = 6) after the start of cortisol infusion. This treatment caused a rise in fetal plasma cortisol similar to that observed at normal delivery. Maternal and fetal progesterone and 20 alpha-dihydroprogesterone concentrations decreased to basal levels during infusion of cortisol to the fetus. Induction of premature delivery was delayed or prevented by concomitant treatment of the ewe with progestagen. Maternal intramuscular injection of 100 mg progesterone, 2 times daily, prevented delivery in four of four ewes treated during the time that cortisol was infused into the fetus (11-13 days). Maternal plasma progesterone and 20 alpha-dihydroprogesterone concentrations were maintained during this period, but fetal plasma progesterone concentrations decreased to the same extent as in the fetuses infused with cortisol alone. A single intramuscular injection of 250 mg of medroxyprogesterone acetate to ewes on the day before commencement of infusion of cortisol to the fetus prevented delivery in four of six ewes during the time that cortisol was infused for 9, 13, 14, and 15 days, respectively. One ewe delivered a live lamb at 133.5 h and another at 147.7 h after the start of infusion of cortisol to the fetus. Maternal and fetal plasma cortisol, progesterone, and 20 alpha-dihydroprogesterone concentrations were similar to those observed during infusion of cortisol alone to the fetus. Although fetal cortisol concentrations rose in a similar fashion, and to a similar extent, in all three groups during infusion of cortisol to the fetus, fetal 11-desoxycortisol concentrations only rose above basal levels close to the time of delivery in cortisol-infused fetuses or, in the progestagen-treated groups, when the fetus showed signs of being stressed.
在向胎儿输注不同剂量皮质醇后，123.5±7.7小时（平均值±标准误，n = 6）出现早产，自开始输注皮质醇起计算。这种处理使胎儿血浆皮质醇升高，与正常分娩时观察到的情况相似。在向胎儿输注皮质醇期间，母体和胎儿的孕酮及20α - 二氢孕酮浓度降至基础水平。给母羊同时使用孕激素可延迟或阻止早产。在向胎儿输注皮质醇期间（11 - 13天），对四只母羊每日两次肌内注射100mg孕酮，可防止这四只母羊分娩。在此期间，母体血浆孕酮和20α - 二氢孕酮浓度得以维持，但胎儿血浆孕酮浓度下降程度与仅输注皮质醇的胎儿相同。在开始向胎儿输注皮质醇前一天，给母羊单次肌内注射250mg醋酸甲羟孕酮，在分别输注皮质醇9、13、14和15天期间，六只母羊中有四只未分娩。在开始向胎儿输注皮质醇后，一只母羊在133.5小时产出一只活羔羊，另一只在147.7小时产出。母体和胎儿血浆皮质醇、孕酮及20α - 二氢孕酮浓度与仅向胎儿输注皮质醇时观察到的相似。尽管在向胎儿输注皮质醇期间，三组胎儿的皮质醇浓度均以相似方式且在相似程度上升，但仅在输注皮质醇的胎儿接近分娩时，或在孕激素处理组中胎儿出现应激迹象时，胎儿11 - 脱氧皮质醇浓度才升至基础水平之上。
