Thomsen J K, Fogh-Andersen N, Jaszczak P, Giese J
Department of Obstetrics and Gynecology, Herlev Hospital, Copenhagen, Denmark.
Acta Obstet Gynecol Scand. 1993 Feb;72(2):103-10. doi: 10.3109/00016349309023421.
Volume regulation and hemodynamic functions change during pregnancy, leading to marked increases in blood volume and cardiac output, peripheral vasodilatation and reduced sensitivity to angiotensin. Atrial natriuretic peptide (ANP) is intimately involved in fluid and sodium homeostasis and exerts marked relaxant activity on vascular smooth muscle pre-contracted with angiotensin. This study was performed to clarify the role of ANP as a regulator of maternal physiology.
40 normal primigravidae were examined five times during pregnancy plus 12 weeks after delivery. Each time were measured: ANP, aldosterone, renin, blood volume (carbon monoxide), cardiac output (Doppler), blood pressure and sodium excretion. Interdependence of the changes in ANP and in the other parameters was tested using Spearman's rank correlation test on the delta (delta)-values (the differences between investigations).
P-ANP in the 20th week was 11.4 (8.5-18.9) pmol.l-1 (median, 25 and 75 percentiles), the same as 12 weeks after delivery, 11.5 (9.6-15.2) pmol.l-1, and in a non-pregnant control group, 10.4 (9.0-12.5) pmol.l-1 (n = 20). All measurements of P-ANP during the 3rd trimester were lower than in the 20th week and 12 weeks after delivery, p < 0.0001 (Wilcoxon matched-pairs test). There was a negative correlation between changes in P-ANP and changes in: a) blood volume. R = 0.69, p < 0.0001, b) aldosterone, R = 0.58, p < 0.0001, c) renin, R = -0.54, p < 0.001, d) cardiac output, R = 0.61, p < 0.001. There was a positive correlation between changes in P-ANP and changes in: a) fractional excretion of sodium, R = 0.54, p < 0.0001, and b) total peripheral resistance. R = 0.52, p < 0.0001.
Decrease in p-ANP is one of the mechanisms whereby blood volume is increased and maintained during pregnancy. The competitive relationship between ANP and the renin aldosterone system in regulating sodium balance and fluid volume is preserved during pregnancy. The results substantiate the physiological importance of ANP as a regulator of blood volume. ANP does not function as a vasodilator during pregnancy.
孕期血容量调节和血流动力学功能发生变化,导致血容量和心输出量显著增加、外周血管舒张以及对血管紧张素的敏感性降低。心房利钠肽(ANP)密切参与体液和钠稳态,并对用血管紧张素预收缩的血管平滑肌发挥显著的舒张活性。本研究旨在阐明ANP作为母体生理调节因子的作用。
对40例正常初产妇在孕期进行5次检查,并在产后12周进行检查。每次测量:ANP、醛固酮、肾素、血容量(一氧化碳)、心输出量(多普勒)、血压和钠排泄量。使用Spearman等级相关检验对差值(δ值,即各次检查之间的差异)进行分析,以检验ANP变化与其他参数变化之间的相关性。
第20周时血浆ANP(P-ANP)为11.4(8.5 - 18.9)pmol·l⁻¹(中位数,第25和75百分位数),与产后12周相同,为11.5(9.6 - 15.2)pmol·l⁻¹,在非孕对照组中为10.4(9.0 - 12.5)pmol·l⁻¹(n = 20)。孕晚期所有P-ANP测量值均低于第20周和产后12周,p < 0.0001(Wilcoxon配对检验)。P-ANP变化与以下各项变化之间存在负相关:a)血容量,R = 0.69,p < 0.0001;b)醛固酮,R = 0.58,p < 0.0001;c)肾素,R = -0.54,p < 0.001;d)心输出量,R = 0.61,p < 0.001。P-ANP变化与以下各项变化之间存在正相关:a)钠分数排泄率,R = 0.54,p < 0.0001;b)总外周阻力,R = 0.52,p < 0.0001。
孕期P-ANP降低是血容量增加并维持的机制之一。孕期ANP与肾素 - 醛固酮系统在调节钠平衡和体液量方面的竞争关系得以保留。结果证实了ANP作为血容量调节因子的生理重要性。孕期ANP不发挥血管舒张剂的作用。