Kitts D D, Anderson G B, BonDurant R H, Stabenfeldt G H
Endocrinology. 1984 Mar;114(3):703-11. doi: 10.1210/endo-114-3-703.
We have examined the relationships among fetal maturity, adrenal steroidogenesis, and initiation of parturition using embryo transfer procedures. Ovine embryos, genetically coded for relatively short [145.5 +/- 1.4 days; Finnish Landrace (Finn)] and long [150.7 +/- 1.3 days; Rambouillet (Ra)] gestational periods, were transferred to a common recipient, thereby facilitating comparative endocrine studies in genetically dissimilar fetuses with a common intrauterine environment. Maternal and fetal plasma samples were obtained daily from chronic fetal lamb preparations in six mixed breed (MB), three Finn, and three Ra single breed (SB) pregnancies during the last trimester and assayed for cortisol, desoxycortisol, and progesterone by RIA. Mean +/- SEM gestational lengths of the forenamed pregnancies were 141.5 +/- 0.7, 141.7 +/- 0.7, and 149.3 +/- 0.9 days, respectively. Time-trend analysis of C-21 steroid data showed an increase in Finn and Ra SB fetal plasma cortisol of 1.0 ng/ml X day at 9.03 +/- 1.0 and 9.58 +/- 1.10 days prepartum, respectively. Significant (P less than or equal to 0.05) differences in the number of days of incremental change (T*) were noted between Finn (10.56 +/- 0.67) and Ra (4.82 +/- 1.08) siblings in MB pregnancies at increment rates of 1.0 ng/ml X day. Similarly, significant (P less than or equal to 0.05) differences in T* values were observed between Finn (8.31 +/- 0.38 days) and RA (4.63 +/- 1.0 days) siblings at 2.0 ng/ml X day. While Finn and Ra SB fetal desoxycortisol T* values were similar at 0.5 and 0.1 ng/ml X day, significant differences (P less than or equal to 0.05) were noted in Finn and Ra cofetuses in the MB pregnancy. Prepartal changes in maternal and fetal progesterone concentrations were correlated, and a direct parallelism was noted between fetal sibling progesterone concentrations. These results are consistent with the view that the fetal genome has a principal role in the timing of parturition.
我们利用胚胎移植程序研究了胎儿成熟度、肾上腺类固醇生成与分娩发动之间的关系。将具有相对较短[145.5±1.4天；芬兰长白（Finn）]和较长[150.7±1.3天；兰布列（Ra）]妊娠期的绵羊胚胎移植到同一个受体中，从而便于在具有共同子宫内环境的基因不同的胎儿中进行比较内分泌研究。在妊娠晚期，每天从六只杂种（MB）、三只Finn和三只Ra单品种（SB）妊娠的慢性胎羊标本中采集母羊和胎儿的血浆样本，并用放射免疫分析法测定皮质醇、脱氧皮质醇和孕酮。上述妊娠的平均±标准误妊娠期分别为141.5±0.7、141.7±0.7和149.3±0.9天。对C-21类固醇数据的时间趋势分析显示，Finn和Ra SB胎儿血浆皮质醇在产前9.03±1.0天和9.58±1.10天分别以1.0 ng/ml·天的速度增加。在MB妊娠中，Finn（10.56±0.67）和Ra（4.82±1.08）同胞之间，以1.0 ng/ml·天的增加速度，在增量变化天数（T*）上存在显著（P≤0.05）差异。同样，在2.0 ng/ml·天的情况下，Finn（8.31±0.38天）和Ra（4.63±1.0天）同胞之间在T值上也观察到显著（P≤0.05）差异。虽然Finn和Ra SB胎儿脱氧皮质醇T值在0.5和0.1 ng/ml·天相似，但在MB妊娠中的Finn和Ra双胎中观察到显著差异（P≤0.05）。母羊和胎儿孕酮浓度的产前变化具有相关性，并且在胎儿同胞孕酮浓度之间观察到直接的平行关系。这些结果与胎儿基因组在分娩时间上起主要作用的观点一致。
