Interactive effects of fluoride and aluminum uptake and accumulation in bones of rabbits administered both agents in their drinking water

Abstract

Fluoride (F) and aluminum (Al), which are known to form a strong complex, are both present in finished drinking water. The effect of F and Al on one another's tissue accumulation was determined using adult male New Zealand white rabbits. Thirty‐six rabbits (three per group) were given Purina Rabbit Chow and drinking water containing no F or AI, F alone (1, A, or 50 ppm F as NaF), Al alone, (100 or 500 ppm Al as AICI₃), or a combination of F and Al, ad libitum for 10 wk. None of these treatments altered food intake or weight gain in these rabbits. However, rabbits treated with 1 ppm F and 500 ppm Al consumed significantly less water than control rabbits. The F accumulation in plasma, urine, incisors, and tibia was increased as the F addition to the drinking water increased within groups receiving a single concentration of Al. In contrast, F accumulation in plasma, urine, incisors, and tibia decreased as the Al concentration increased within groups receiving a single F concentration, indicative of decreased intestinal absorption. Importantly, Al levels in tibia were significantly increased by the addition of F to the drinking water, even in animals receiving no Al in their drinking water. The effect of F on Al accumulation in bone was confirmed by our evaluating Al levels in sterna harvested from rats treated with 0 or 79 ppm F (as NaF in the drinking water) in a study conducted by the National Toxicology Program (Bucher et al., 1991). Therefore, some of the osteotoxicity seemingly associated with high F levels in bone may be due to the accumulation of Al or an Al‐F complex.