Gastrointestinal absorption, tissue retention, and urinary excretion of dietary aluminum in rats determined by using 26Al

Abstract

We used accelerator mass spectrometry (AMS) and 26Al to study the plasma concentration, urinary excretion, and retention in bone, brain, and liver of a single dose of a dietary concentration of aluminum ingested either with or without citrate by 2-month-old Wistar rats. In the absence of citrate, cumulative urinary excretion and skeleton retention were each ~0.05% of the total 26Al dose ingested. 26Al retention in brain and liver were ~4 x 10-8 and 2 x 10-6, respectively. Concomitant citrate intake increased these median values by about two- to fivefold, although this factor was highly variable in individual rats. Independent of citrate administration, 90% of the 26Al excreted in urine (measured cumulatively over 30 days) was excreted within the first 48 h. Uptake by bone was rapid (~1 h) and permanent over the 30-day duration of the experiment.