Experimental obstructive hydronephrosis in newborn rats. VI. Long-term effects on glomerular filtration and distribution.

Partial obstruction of one ureter was created in newborn rats and its effects were studied after the rats matured. The obstructed pelvis was found to be considerably enlarged. The parenchymal weight was 19 per cent lower and the whole kidney glomerular filtration rate was 43 per cent lower than on the contralateral intact side (p less than 0.001); however, these figures probably include a compensatory increase on the intact side. In the central part of the cortex, the glomerular filtration rate/mg. cortex was 21 per cent lower in the hydronephrotic kidney (p less than 0.02), but there was no intracortical redistribution. The glomerular density in this region was 24 per cent higher on the hydronephrotic side (p less than 0.001), because the glomeruli were crammed together in the distended cortex. No redistribution of glomeruli was found. The results are discussed and compared with previous findings from our laboratory. In this model, partially obstructive uropathy was found to cause only a moderate depression, but no redistribution, of the filtration.