INTESTINAL-ABSORPTION OF ALUMINUM - EFFECT OF SODIUM AND CALCIUM

Aluminium (Al) is recognized as a toxin in patients with deficient ren al function. Moreover, Al may play a role in some neurodegenerative di seases. It is hypothesized that more than one intestinal absorption me chanism exists for Al, related to various intraluminal chemical specie s, and that Al shares intestinal transport routes for essential inorga nic substances due to similarities in their chemical speciation charac teristics. The purpose of the present investigation was to study the e ffects of ionic Na (0-120 mmol/l) and Ca (0-10 mmol/l), alone and in c ombination, on the intestinal absorption of ionic Al (20 and 30 mmol/l ). A previously standardized method of perfusion of rat small intestin e was used, combined with serial blood sampling. Mucosal uptake and sy stemic appearance of Al in the blood were monitored during 1 h perfusi on, together with Na and Ca; the metals were given as the chloride. Th e intestinal absorption of Na and Ca was taking place according to pre viously reported mechanisms. A one-sided negative interaction was show n to exist between Ca and Al resp. Al and Na during both mucosal uptak e and systemic appearance; Ca interacts negatively with Na during syst emic appearance, but enhances mucosal uptake of Na. It may be speculat ed that Al mimicks Ca in its Na-dependent intestinal passage.