Klemcke H G, Christenson R K
USDA-ARS, Roman L. Hruska U.S. Meat Animal Research Center, Clay Center, Nebraska 68933-0166, USA.
Biol Reprod. 1997 Jul;57(1):99-106. doi: 10.1095/biolreprod57.1.99.
A study was conducted to characterize fetal plasma ACTH and corticosteroid concentrations during porcine gestation and to relate plasma corticosteroids to fetal size. Samples were taken in white crossbred pigs at 50, 75, and 100 days of gestation and in Chinese Meishan pigs at Day 75. Fetuses developed in either "crowded" or "roomy" uterine environments after maternal uterine ligation, and all fluid samples were obtained during surgery. Fetal arterial cortisol decreased by 30% between Days 50 and 75 and then increased by 101% between 75 and 100 days. Concomitantly, fetal arterial ACTH increased 4-fold between 50 and 75 days of gestation and 45% between 75 and 100 days. Fetal venous cortisol and ACTH (measured only on Days 75 and 100) concentrations were lower than arterial concentrations. Both amniotic and allantoic fluid cortisol concentrations paralleled those of arterial cortisol but were at least 4-fold less. The percentage of free cortisol on Days 75 and 100 was a constant 24%, whereas cortisol bound to corticosteroid-binding globulin was a constant 60% and albumin-bound cortisol was 16%. White crossbred fetal arterial cortisone concentrations were always lower than cortisol concentrations, did not differ between arterial and venous plasma, decreased 50% between 50 and 75 days, and did not change thereafter. Plasma cortisol concentrations in Chinese Meishan fetuses were 30% greater than in white crossbred fetuses of the same age, but plasma ACTH and cortisone did not differ between breeds. Analysis of covariance indicated a negative regression of fetal weight and fetal length on arterial cortisol in white crossbred fetuses only at Day 100, and at Day 75 in Meishan fetuses. Under the specific conditions of this experimental model, these data demonstrate prenatal developmental changes in plasma ACTH and corticosteroids, indicate breed differences in such development, and suggest that a negative relationship exists between endogenous cortisol concentrations and fetal size at specific gestational ages.
本研究旨在描述猪妊娠期胎儿血浆促肾上腺皮质激素（ACTH）和皮质类固醇浓度的特征，并探讨血浆皮质类固醇与胎儿大小的关系。在白色杂交猪妊娠50、75和100天时以及中国梅山猪妊娠75天时采集样本。通过母体子宫结扎，使胎儿在“拥挤”或“宽松”的子宫环境中发育，所有液体样本均在手术期间获取。胎儿动脉血皮质醇在50至75天之间下降了30%，然后在75至100天之间增加了101%。与此同时，胎儿动脉血ACTH在妊娠50至75天之间增加了4倍，在75至100天之间增加了45%。胎儿静脉血皮质醇和ACTH（仅在75天和100天测量）浓度低于动脉血浓度。羊水和尿囊液皮质醇浓度与动脉血皮质醇浓度平行，但至少低4倍。75天和100天时游离皮质醇的百分比恒定为24%，而与皮质类固醇结合球蛋白结合的皮质醇恒定为60%，与白蛋白结合的皮质醇为16%。白色杂交胎儿动脉血可的松浓度始终低于皮质醇浓度，动脉血和静脉血血浆中无差异，在50至75天之间下降了50%，此后无变化。中国梅山胎儿的血浆皮质醇浓度比同龄白色杂交胎儿高30%，但血浆ACTH和可的松在品种间无差异。协方差分析表明，仅在100天时白色杂交胎儿以及75天时梅山胎儿中，动脉血皮质醇与胎儿体重和胎儿长度呈负相关。在本实验模型的特定条件下，这些数据证明了血浆ACTH和皮质类固醇的产前发育变化，表明了这种发育的品种差异，并提示在特定胎龄时内源性皮质醇浓度与胎儿大小之间存在负相关关系。
