GASTROINTESTINAL ABSORPTION, TISSUE RETENTION, AND URINARY-EXCRETION OF DIETARY ALUMINUM IN RATS DETERMINED BY USING AL-26

We used accelerator mass spectrometry (AMS) and Al-26 to study the pla sma concentration, urinary excretion, and retention in bone, brain, an d liver of a single dose of a dietary concentration of aluminum ingest ed either with or without citrate by 2-month-old Wistar rats. In the a bsence of citrate, cumulative urinary excretion and skeleton retention were each similar to 0.05% of the total Al-26 dose ingested. Al-26 re tention in brain and liver were similar to 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 i n individual rats. Independent of citrate administration, 90% of the A l-26 excreted in urine (measured cumulatively over 30 days) was excret ed within the first 48 h. Uptake by bone was rapid (similar to 1 h) an d permanent over the 30-day duration of the experiment.