Natriuretic effectiveness of bumetanide in rats with immature kidney function.

The influence of bumetanide on renal excretion of water and electrolytes was measured in saline loaded rats of various ages. The relative increase in sodium excretion following bumetanide administration is more pronounced in 5 and 15 day old rats than in older animals. The lower natriuretic potency of bumetanide in adult rats is not limited by the administered sodium dose since an additional sodium load does not provoke a more pronounced sodium excretion in these animals.