Balance of net base in the rat. III. Effects of oral sodium bicarbonate and sodium citrate loading.

The balance of net base in groups of male weanling Wistar rats exposed to sustained oral loads of net base were studied. In response to dietary loads of sodium bicarbonate (approx. 50 mmol.kg-1.day-1) an average increment in the mean rate of retention of net base of 21.8 mmol.kg-1.day-1 was observed in the absence of significant changes in the blood 'base excess'. Following withdrawal of sodium bicarbonate, mean rates of gastrointestinal absorption, renal excretion, and retention of net base promptly returned to control values, accumulated net base being retained in the body, presumably as skeletal sodium carbonate. In response to equimolar loads of net base in the form of trisodium citrate, a similar, albeit less pronounced, rise in the rate of retention of net base occurred.