Dickson K A, Harding R
Department of Physiology, Monash University, Clayton, Victoria, Australia.
Exp Physiol. 1994 Mar;79(2):147-60. doi: 10.1113/expphysiol.1994.sp003748.
Our aim was to determine the importance of amniotic and allantoic fluids for the maintenance of fetal plasma composition during maternal dehydration when water transfer from mother to fetus is likely to be reduced. Eight pregnant ewes were studied before, during and after water deprivation (36 h), firstly with the fetal fluid sacs intact and then with them drained of fluid for 5 days. When water deprivation was combined with drainage, the increases in the osmolalities, [Na+] and [Cl-] in maternal plasma, in fetal plasma and in lung liquid; the increases in fetal urinary osmolality and [Na+]; and the increases in maternal plasma and fetal plasma arginine vasopressin concentrations were greater than those resulting from water deprivation alone. Our results show that during maternal water deprivation, an absence of fluid in the fetal sacs increases both the osmotic stimulus to the fetus and the fetal responses resulting in conservation of water and salt. We conclude that, when the mother is deprived of water, fluid in the fetal sacs is used to limit the degree of maternal and fetal dehydration.
我们的目的是确定当母体脱水时羊水和尿囊液对于维持胎儿血浆成分的重要性，此时从母体到胎儿的水分转移可能会减少。对8只怀孕母羊在禁水前、禁水期间（36小时）和禁水后进行研究，首先胎儿液囊完整，然后将其排空5天。当禁水与排空相结合时，母体血浆、胎儿血浆和肺液中渗透压、[Na⁺]和[Cl⁻]的升高；胎儿尿渗透压和[Na⁺]的升高；以及母体血浆和胎儿血浆中精氨酸加压素浓度的升高均大于仅由禁水导致的升高。我们的结果表明，在母体禁水期间，胎儿囊内无液体增加了对胎儿的渗透刺激以及胎儿为保存水和盐而产生的反应。我们得出结论，当母体缺水时，胎儿囊内的液体用于限制母体和胎儿脱水的程度。
