ABSORBED ALUMINUM IS FOUND WITH 2 CYTOSOLIC PROTEIN-FRACTIONS, OTHER THAN FERRITIN, IN THE RAT DUODENUM

After in vivo perfusion of the upper intestine of the rat with a range of concentrations of aluminium chloride, entry of the metal into the portal system was only detected when the perfusate exceeded 400 mumol/ l, suggesting a mucosal block.- Using gel filtration of a mucosal cyto sol extract, two consistently appearing aluminium peaks were identifie d which may represent aluminium binding proteins. Both were heat stabl e at 60-degrees-C and had molecular sizes of about 700 (kilo daltons) (kD) and 17 kD respectively. The larger molecule was distinct from fer ritin. Neither molecule associated with Fe-59 nor Ca-45. It is suggest ed that the aluminium peaks are relatively specific aluminium binding proteins that have a scavenging role, reducing entry of the metal from the intestinal contents into the portal blood.