The influence of the administration of thiamine (vitamin B1), ascorbic acid (vitamin C) or their combination on the efficacy of two thiol metal chelators, viz. alpha-mercapto-beta-(2-furyl) acrylic acid (MFA) and 2,3-dimercaptosuccinic acid (DMS), in counteracting lead (Pb) toxicity was investigated in rats. Ascorbic acid or its combination with thiamine enhanced the urinary elimination of Pb, reduced the hepatic and renal burden of Pb, and reversed the Pb-induced inhibition of the activity of blood delta-aminolevulinic acid dehydratase (delta-ALA-D). All these effects were more evident in DMS- than in MFA-treated rats. The combination of MFA and DMS treatments further improved the performance of the animals in enhancing urinary Pb excretion and in reducing Pb hepatic levels.

The effects of the daily administration of aluminium (25 mg kg-1, orally), ethanol (10% v/v, in drinking water) or both to adult rats, for 6 weeks, on the amount of aluminium present in the tissues and the functioning of brain biogenic amines, hepatic and serum transaminases and some haematopoietic variables were investigated. Ethanol alone was seen to inhibit the activity of δ-aminolevulinic acid dehydratase (ALAD), while aluminium alone elevated the activity of blood ALAD. However, aluminium and ethanol combined produced a more pronounced inhibition of blood ALAD and hepatic glutamic pyruvic transminase (GPT) than either aluminium or ethanol alone. Simultaneous exposure to aluminium and ethanol also produced a significant elevation in urinary δ-aminolevulinic acid (ALA) blood zinc protoporphyrin (ZPP), serum glutamic oxaloacetic transaminase (GOT) and brain homovanillic acid (HVA), and a depletion in brain dopamine (DA) and 5-hydroxytryptamine (5-HT) levels, when compared to rats given aluminium alone. The concentration of aluminium in the blood and liver was significantly higher in rats exposed to both aluminium and ethanol than in those exposed to aluminium alone. Thus the consumption of alcohol may increase the rat's susceptability to certain effects of aluminium.

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