Vokes T J, Weiss N M, Schreiber J, Gaskill M B, Robertson G L
Department of Medicine, University of Chicago, Pritzker School of Medicine, Illinois 60637.
Am J Physiol. 1988 Apr;254(4 Pt 2):R641-7. doi: 10.1152/ajpregu.1988.254.4.R641.
Changes in osmoregulation during normal menstrual cycle were examined in 15 healthy women. In 10 women, studied repetitively during two consecutive menstrual cycles, basal plasma osmolality, sodium, and urea decreased by 4 mosmol/kg, 2 meq/l, and 0.5 mM, respectively (all P less than 0.02) from the follicular to luteal phase. Plasma vasopressin, protein, hematocrit, mean arterial pressure, and body weight did not change. In five other women, diluting capacity and osmotic control of thirst and vasopressin release were assessed in follicular, ovulatory, and luteal phases. Responses of thirst and/or plasma vasopressin, urine osmolality, osmolal and free water clearance to water loading, and infusion of hypertonic saline were normal and similar in the three phases. However, the plasma osmolality at which plasma vasopressin and urine osmolality were maximally suppressed as well as calculated osmotic thresholds for thirst and vasopressin release were lower by 5 mosmol/kg in the luteal than in the follicular phase. This lowering of osmotic thresholds for thirst and vasopressin release, which occurs in the luteal phase, is qualitatively similar to that observed in pregnancy and should be taken into account when studying water balance and regulation of vasopressin secretion in healthy cycling women.
对15名健康女性正常月经周期中的渗透调节变化进行了研究。在连续两个月经周期中重复研究的10名女性中，从卵泡期到黄体期，基础血浆渗透压、钠和尿素分别下降了4 mosmol/kg、2 meq/l和0.5 mM（所有P均小于0.02）。血浆血管加压素、蛋白质、血细胞比容、平均动脉压和体重均未改变。在另外5名女性中，在卵泡期、排卵期和黄体期评估了口渴和血管加压素释放的稀释能力及渗透控制。在这三个阶段，口渴和/或血浆血管加压素、尿渗透压、渗透和自由水清除率对水负荷以及高渗盐水输注的反应正常且相似。然而，黄体期血浆血管加压素和尿渗透压被最大程度抑制时的血浆渗透压以及计算得出的口渴和血管加压素释放的渗透阈值比卵泡期低5 mosmol/kg。黄体期出现的口渴和血管加压素释放渗透阈值的降低在性质上与妊娠时观察到的相似，在研究健康育龄女性的水平衡和血管加压素分泌调节时应予以考虑。
