Volumes of distribution of sodium and albumin in the sheep placenta.

Publisher Website
Google Scholar
Abstract
The volumes of distribution of 22Na and 24Na, 51Cr-EDTA and albumin labeled with 131I and 125I were measured in cotyledons and skeletal muscle taken from pregnant sheep and the fetuses near term. Radiolabeled substances were injected through chronically implanted catheters 0.5-3.2 h before removal of tissues in short-term experiments and 24-26 h before in long-term experiments. Volumes of distribution were expressed as percentages of tissue weights. Cotyledonary water content was 81.5 .+-. 0.6% (SE of mean) of wet weight (n = 10 sheep). Na content was 76.0 .+-. 4.0 m-mole kg-1 wet weight (n = 4) and K content was 58.8 .+-. 2.4 m-mol .mu. kg-1 wet weight (n = 4). In short-term studies cotyledonary spaces following injection into the fetal circulation were: Na, 20.5 .+-. 0.9% (n = 10 sheep); Cr-EDTA, 19.5 .+-. 1.2% (n = 3) and albumin, 2.8 .+-. 0.3% (n = 11). The equivalent maternal cotyledonary spaces were: Na, 23.5 .+-. 1.6%, or 22.1 .+-. 1.6% when corrected for fetal radioactivity (n = 8); and albumin, 4.7 .+-. 0.8% (n = 8). Maternal and fetal cotyledonary Na spaces were additive. Larger cotyledons had larger fetal Na spaces. In long-term studies, the value for maternal albumin spaces was considerably higher 12.3 .+-. 3.2% (n = 3), whereas that for fetal albumin spaces was only 3.9 .+-. 0.4% (n = 4). The higher fetal Na space of 24.9 .+-. 1.0% (n = 4) in the long-term experiments was attributable to rising Na counts in the maternal circulation. In the short-term experiments maternal skeletal muscle spaces were Na, 13.5 .+-. 1.3% (n = 7) and albumin, 1.7 .+-. 0.3% (n = 7), with higher values of 22.0% (n = 2) and 3.8 .+-. 0.2% (n = 3), respectively, in long-term experiments. In the short-term experiments, fetal skeletal muscle spaces were Na, 32.8 .+-. 3.2% (n = 7) and albumin, 2.5 .+-. 0.3% (n = 10), with higher values of 39.7 .+-. 7.4% (n = 4) and 16.2 .+-. 0.6% (n = 4), respectively, in long-term experiments.

This publication has 13 references indexed in Scilit: