Comparative aluminium mobilizing actions of deferoxamine and four 3-hydroxypyrid-4-ones in aluminium-loaded rats

The efficacy of the Al chelating drugs deferoxamine (DFO) a nd the hydoxypyridones (HPs): 1,2-dimethyl-3-hydroxypyrid-4-one (L1), 1-[3-hydroxy-2-methyl-4-oxopyridyl]-2-ethanesulfonic acid (L6), 1-benzyl-(4-carboxylic acid)-3-hydroxy-2-methyl-4-oxopyridine (Bzcal) and 1-(p-methylbenzyl)-2-ethyl-3-hydroxypyrid-4-one (MeBzEM) in increasing Al excretion and reducing tissue Al accumulation has been compared in adult male rats which had previously received Al nitrate nonahydrate i.p. at 0.16 mmol/kg per day for 2 months. At the end of this period, DFO was injected s.c. and the HPs were given by gavage at 0.89 mmol/kg per day for five consecutive days. Total urines were collected 24 h after each chelalor administration. Following chelation treatment animals were killed and samples of brain, bone, liver, kidney, and spleen were collected. DFO administration increased to about 4 x the cumulative urinary Al elimination for 5 days, while the excretion of Al into urine caused by Bzcal, L1, and MeBzEM administration was about twice that of the control group. On the other hand, treatment with Bzcal, DFO, and MeBzEM for 5 days significantly reduced the Al levels in bone by 31, 33, and 29%, and the Al concentrations in brain by 46, 69, and 71%, respectively. These results suggest that oral administrations of MeBzEM and Bzcal can be potential alternatives to parenteral administration of DFO in Al removal. (C) 1998 Elsevier Science Ireland Ltd. All rights reserved.