AJP - Gastrointestinal and Liver Physiology, Vol 249, Issue 2 209-G213, Copyright © 1985 by American Physiological Society
Duodenal aluminum absorption in the rat: effect of vitamin D
A. J. Adler and G. M. Berlyne
Aluminum absorption by the duodenum was studied with an in vivo isolated
gut segment technique in vitamin D-deficient and vitamin D-replete rats.
Aluminum uptake could be resolved into saturable and nonsaturable
components. Both groups demonstrated an identical nonsaturable mechanism
with an aluminum uptake of approximately 23% of the amount perfused per 100
mg dry intestinal weight. Saturable absorption was significantly lower in
the vitamin D-deficient group (Jmax 6.9 +/- 1.4 microM X h-1 X 100 mg dry
wt-1) than in the vitamin D-replete group (Jmax 13.0 +/- 2.7 microM X h-1 X
100 mg dry wt-1) (P less than 0.05). The presence of aluminum in the
perfusion solutions reduced duodenal calcium absorption by 33% (P less than
0.02) in the vitamin D-replete group but not the vitamin D-deficient group.
These results suggest that aluminum is absorbed in the duodenum by both a
nonsaturable mechanism and a vitamin D-dependent saturable mechanism, for
which it may compete with calcium.
