Vaklotton M B, Davison J M, Riondel A M, Lindheimer M D
Clin Exp Hypertens B. 1982;1(2-3):385-400. doi: 10.3109/10641958209139861.
Amongst the man physiological changes in human pregnancy are the sustained stimulation of the renin-angiotensin system and a decreases in plasma osmolality (Posm). In this study the effect osmolar and water loading on the renin-angiotensin system and arginine vasopressin (AVP) secretion has been tested in seven women during the third trimester and again 8-10 weeks after delivery. Pregnant women had markedly increased plasma renin substrate (PRS), plasma renin activity (PRA) and plasma renin concentration (PRC) values as well as aldosterone levels when compared to their post-partum values. Osmolar loading with intravenous infusion of hypertonic saline resulted in a decrease in PRA and aldosterone levels both during and after pregnancy but even at the end of the infusion the pregnant women still had values greater than the pre-infusion levels obtained post-partum. Surprisingly, oral water loading also significantly decreased PRA and aldosterone levels in pregnancy, possibly related to the redistribution of extracellular fluid centrally when the pregnant women were in left lateral recumbency. Despite the decreased basal Posm of pregnancy, urinary AVP increased and decreased appropriately during osmolar and water loading. Exact characterisation of the resetting of the threshold for AVP secretion in pregnancy awaits the development of a reliable radioimmunoassay for the determination of AVP in human pregnancy plasma.
在人类妊娠期间的众多生理变化中，肾素 - 血管紧张素系统会持续受到刺激，血浆渗透压（Posm）会降低。在本研究中，对7名处于孕晚期的女性以及产后8 - 10周的女性，测试了渗透压和水负荷对肾素 - 血管紧张素系统及精氨酸加压素（AVP）分泌的影响。与产后值相比，孕妇的血浆肾素底物（PRS）、血浆肾素活性（PRA）、血浆肾素浓度（PRC）值以及醛固酮水平均显著升高。静脉输注高渗盐水进行渗透压负荷试验，结果显示孕期及产后PRA和醛固酮水平均下降，但即使在输注结束时，孕妇的值仍高于产后输注前的水平。令人惊讶的是，口服水负荷也显著降低了孕期的PRA和醛固酮水平，这可能与孕妇左侧卧位时细胞外液向中央重新分布有关。尽管孕期基础Posm降低，但在渗透压和水负荷期间，尿AVP会相应地增加和减少。孕期AVP分泌阈值重置的精确特征还有待开发一种可靠的放射免疫分析法来测定人妊娠血浆中的AVP。
