Department of Medicine, University of Otago, Christchurch 8015, New Zealand.
Pediatr Res. 2010 Dec;68(6):462-5. doi: 10.1203/PDR.0b013e3181f9039d.
We have used aminoterminal pro C-type natriuretic peptide (NTproCNP)--a stable marker of CNP secretion--to study the effect of cortisol on CNP secretion and fetal growth. In ovine pregnancy, maternal plasma NTproCNP (largely sourced from the placenta) increases at the end of the first trimester and then decreases abruptly preterm during the phase of fetal surge in cortisol secretion. Postulating that increases in cortisol, as occurs in the fetal or maternal circulation in late pregnancy, will reduce CNP secretion, we studied the fetal and maternal responses in NTproCNP to sustained low-dose infusions of cortisol (1.2 mg/d/kg for 11 d) delivered to the fetus from d 117 gestation. Fetal plasma NTproCNP was progressively reduced during fetal cortisol infusions, whereas fetal girth growth was unchanged. In contrast, maternal NTproCNP was unaffected by cortisol. We conclude that fetal but not placental tissue production of CNP is reduced by small increments in fetal cortisol. Failure to reduce maternal NTproCNP may relate to the continuing presence of the placental barrier to cortisol at this stage of pregnancy.
我们使用氨基末端 pro C 型利钠肽（NTproCNP）——一种 CNP 分泌的稳定标志物——来研究皮质醇对 CNP 分泌和胎儿生长的影响。在绵羊妊娠中，母体血浆 NTproCNP（主要来源于胎盘）在第一 trimester 末期增加，然后在胎儿皮质醇分泌激增的阶段突然提前减少。推测在妊娠晚期胎儿或母体循环中皮质醇的增加会减少 CNP 的分泌，因此我们研究了 NTproCNP 对持续低剂量皮质醇（1.2 mg/d/kg）输注的胎儿和母体反应，从妊娠第 117 天开始输注。在胎儿皮质醇输注期间，胎儿血浆 NTproCNP 逐渐减少，而胎儿周长生长不变。相比之下，皮质醇对母体 NTproCNP 没有影响。我们得出结论，小幅度增加胎儿皮质醇会减少胎儿而非胎盘组织产生的 CNP。未能降低母体 NTproCNP 可能与妊娠的这一阶段胎盘对皮质醇的持续存在有关。
