Silver M, Fowden A L, Knox J, Ousey J, Cash R, Rossdale P D
Physiological Laboratory, Cambridge, U.K.
J Reprod Fertil Suppl. 1991;44:619-26.
Pre- and post partum changes in plasma T3 have been examined in relation to plasma cortisol in 23 newborn foals (12 full term, 6 premature and 5 'twilight'), and in 5 fetuses catheterized in late gestation. Blood samples were collected daily from the fetuses and from the neonates at 30-min intervals for 2 h after birth; the plasma was assayed for T3 and cortisol by standard radioimmunoassay methods. In the full-term foals, plasma cortisol and T3 concentrations were high at birth (67.4 +/- 6.1 and 4.3 +/- 0.3 ng/ml respectively) and rose to a maximum during the following 2-h period to 141.0 +/- 8.8 ng/ml and 8.4 +/- 0.5 ng/ml. The corresponding changes in the premature foals over the same period were significantly lower (P less than 0.01; 17.2 +/- 2.2 to 27.0 +/- 4.3 ng cortisol/ml and 2.9 +/- 0.5 to 5.4 +/- 0.6 ng T3/ml). In the 'twilight' group, intermediate increases in both cortisol and T3 were observed. In the 5 chronically catheterized fetuses, both plasma cortisol and T3 were low in the last few weeks of gestation (7.0 +/- 1.1 ng/ml and 1.2 +/- 0.2 ng/ml respectively). In 2 fetuses there was little or no increase in plasma cortisol or T3 before induction of labour at about 320 days; one foal was premature and the other 'twilight'. Infusion of adrenocorticotrophic hormone for 4.5 days into the third fetus from 309 days led to an increase in both cortisol and T3 and the birth of a viable, full term foal. The 2 remaining fetuses were delivered spontaneously, one at term and one at 300 days (well before term). The latter was viable but dysmature; it showed a slight prenatal rise in plasma cortisol with little change in T3. When all the data were combined from both fetuses and neonates a significant positive correlation between plasma T3 and cortisol was found (P less than 0.001). These results demonstrate a relationship between circulating cortisol and T3 in the perinatal period and show that prematurity is associated with low concentrations of both hormones.
对23匹新生马驹（12匹足月、6匹早产和5匹“过渡型”）以及5匹在妊娠晚期进行导管插入术的胎儿，研究了产后血浆T3与血浆皮质醇的变化关系。从胎儿和出生后2小时内每隔30分钟的新生儿处每日采集血样；采用标准放射免疫分析方法测定血浆中的T3和皮质醇。在足月马驹中，出生时血浆皮质醇和T3浓度较高（分别为67.4±6.1和4.3±0.3 ng/ml），并在随后的2小时内升至最高，分别为141.0±8.8 ng/ml和8.4±0.5 ng/ml。同期早产马驹的相应变化显著较低（P＜0.01；皮质醇从17.2±2.2升至27.0±4.3 ng/ml，T3从2.9±0.5升至5.4±0.6 ng/ml）。在“过渡型”组中，观察到皮质醇和T3均有中等程度的升高。在5匹长期进行导管插入术的胎儿中，妊娠最后几周血浆皮质醇和T3均较低（分别为7.0±1.1 ng/ml和1.2±0.2 ng/ml）。在2例胎儿中，约320天时引产之前血浆皮质醇或T3几乎没有增加；一匹马驹早产，另一匹为“过渡型”。从309天起，对第三例胎儿连续4.5天输注促肾上腺皮质激素导致皮质醇和T3均增加，并产下一匹存活的足月马驹。其余2例胎儿自然分娩，一例足月，一例在300天（远未足月）。后者存活但发育不全；产前血浆皮质醇略有升高，T3变化不大。当将胎儿和新生儿的所有数据合并时，发现血浆T3与皮质醇之间存在显著正相关（P＜0.０01）。这些结果证明围产期循环皮质醇与T3之间存在关联，并表明早产与两种激素的低浓度有关。
