Effects of maternal bilateral ureteral ligation on the differentiation of glomerular anionic sites in fetal rat kidney.

Effects of maternal bilateral ureteral ligation on the differentiation of glomerular anionic sites in fetal kidney were studied with the colloidal iron method. The ligation was performed on days 17, 19, and 21 of pregnancy, and the animal were euthanized 1 day after each ligation. On fetal day 20, in the fetuses from ligated mothers, colloidal iron was concentrated in laminae rarae interna and externa of the glomerular basement membrane. In the fetuses from sham-ligated mothers, however, a different pattern of iron distribution was noted. In most areas of the glomerular basement membrane, colloidal iron was randomly distributed as in both fetuses of fetal day 18. In the remaining areas, the same pattern of colloidal iron distribution as was noted in the fetuses from ligated mothers of fetal day 20 was observed. On fetal day 22, colloidal iron was densely accumulated in laminae rarae interna and externa of the glomerular basement membrane in both groups. However, the iron-free zone was slightly thicker in the fetuses from the ligated mothers. These findings suggest that maternal bilateral ureteral ligation accelerates the differentiation of glomerular anionic sites in the kidney of fetal rats.