Impact of age on effects of ureteral obstruction on renal function

Abstratc Impact of age on effects of ureteral obstruction on renal function. Chronic partial ureteral obstruction of the urinary tract is a common congenital abnormality. Yet, its impact on the function of the kidney in the young has not been examined. To determine the relationship between age at the time of injury and outcome, partial ureteral obstruction was produced in guinea pigs during the first, second, third, fourth, or fifth week of life, and several variables of glomerular, proximal and distal tubular functions were measured 4 weeks later. The results were compared with those obtained in the contralateral kidney and with those observed in age-matched sham-operated animals. There was a significant impairment in the growth of the obstructed kidney. The weight of the contralateral kidney in the experimental animals was significantly greater than that of the obstructed (P Osm on the obstructed side was markedly and uniformly reduced being 1.0 ± 0.1 in animals obstructed either at 1 or 5 weeks of age. Thus, the effect of chronic partial ureteral obstruction on glomerular and proximal tubular function is more severe in the young than in the old animal, whereas functions located in distal tubular segments appear to be affected to a similar extent at all ages. The ability of the contralateral kidney to adapt is directly and quantitatively related with the capacity of the organ to undergo compensatory hypertrophy and consequently decreases with the age of the animal. Impact de l'âge sur les effets de l'obstruction ureterale sur la fonction renale. L'obstruction ureterale chronique partielle du tractus urinaire est une anomalie congenitale commune. Cependant, son impact sur la fonction du rein chez le jeune n'a pas ete examine. Afin de determiner la relation entre l'âge au moment de la lesion et le devenir, une obstruction ureterale partielle a ete produite chez des cobayes pendant la premiere, la seconde, la troisieme, la quatrieme, ou la cinquieme semaine de vie, et plusieurs variables des fonctions glomerulaires et tubulaires proximales et distales ont ete mesurees 4 semaines plus tard. Les resultats ont ete compares avec ceux obtenus sur le rein controlateral, et avec ceux observes chez des animaux du meme âge, ayant subi un simulacre d'operation. Il y avait une alteration significative de la croissance du rein obstrue. Le poids du rein controlateral chez les animaux experimentaux etait significativement plus eleve que celui du rein obstrue (P Osm du cote obstrue etait reduit de facon marquee et uniforme, etant 1,0 ± 0,1 chez les animaux mis en obstruction a un âge de 1 ou 5 semaines. Ainsi l'effet de l'obstruction ureterale partielle chronique sur la fonction glomerulaire et tubulaire proximale est plus severe chez l'animal jeune que chez l'animal âge, tandis que les fonctions situees dans les segments tubulaires distaux semblent etre affectees d'une maniere identique a tous les âges. La capacite du rein controlateral de s'adapter est directement et quantativement reliee a la capacite de l'organe de subir une hypertrophie compensatrice, et donc diminue avec l'âge de l'animal.