Diffusion permeability of the immature placenta of the rabbit embryo to inert hydrophilic molecules.
Diffusion permeability of the immature placenta of the rabbit embryo to inert hydrophilic molecules.
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兔胚胎未成熟胎盘对惰性亲水分子的扩散渗透性。
DOI：
10.1152/ajpheart.1993.265.5.h1804
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发表时间：
1993
期刊：
影响因子：
--
通讯作者：
Faber,JJ
中科院分区：
文献类型：
--
作者：
Faber,JJ
在妊娠 13-15 天（足月，31 天）的兔胎盘中测定一系列亲水性探针（半径为 2-10 A）的清除率。通过放射性标记的微球测量母体胎盘血流量。示踪剂的转移均不受胎盘中母体或胚胎动静脉差异的限制，并且清除率随着分子半径的增加而降低。根据概念生长计算出的经胎盘水滤过率在大小上与最大示踪剂的清除率相当。 Patlak 对赫兹方程和孔隙理论的修改的应用表明，等效孔隙半径为 17 A。随着分子尺寸的增加，根据该值计算出的胎盘渗透性表面积乘积比测量的间隙急剧下降，这表明尽管在实验条件下存在非常大的扩散梯度，但过滤的贡献非常显着。结果表明，体内血绒胚胎胎盘的尺寸选择性不是很显着，在正常条件下，母体血浆的滤液构成了胚胎供应的主要贡献者。
The clearances of a series of hydrophilic probes (radii of 2-10 A) were determined in rabbit placentas of 13-15 days of gestation (term, 31 days). Maternal placental blood flows were measured by means of radiolabeled microspheres. None of the transfers of the tracers were limited by maternal or embryonic arteriovenous differences in the placenta, and the clearances decreased with increasing molecular radius. The transplacental water filtration rate calculated from conceptual growth was comparable in magnitude to the clearances of the largest tracers. Application of Patlak's modification of the Hertzian equation and pore theory suggested an equivalent pore radius of 17 A. Placental permeability surface area products computed from this value decreased much more steeply with increasing molecular dimension than the measured clearances, suggesting a highly significant contribution by filtration despite the very large diffusional gradients that existed under the experimental conditions. The results indicate that the size selectivity of the hemochorial embryo placenta in vivo is not very significant, and that under normal conditions filtrate of maternal plasma constitutes a major contributor to embryonic supply.