title: Metabolism and possible health effects of aluminum.
abstract: Literature regarding the biochemistry of aluminum and eight similar ions is reviewed. Close and hitherto unknown similarities were found. A hypothetical model is presented for the metabolism, based on documented direct observations of Al3+ and analogies from other ions. Main characteristics are low intestinal absorption, rapid urinary excretion, and slow tissue uptake, mostly in skeleton and reticuloendothelial cells. Intracellular Al3+ is probably first confined in the lysosomes but then slowly accumulates in the cell nucleus and chromatin. Large, long-lived cells, e.g., neurons, may be the most liable to this accumulation. In heterochromatin, Al3+ levels can be found comparable to those used in leather tannage. It is proposed that an accumulation may take place at a subcellular level without any significant increase in the corresponding tissue concentration. The possible effects of this accumulation are discussed. As Al3+ is neurotoxic, the brain metabolism is most interesting. The normal and the lethally toxic brain levels of Al3+ are well documented and differ only by a factor of 3-10. The normal brain uptake of Al3+ is estimated from data on intestinal uptake of Al3+ and brain uptake of radionuclides of similar ions administered intravenously. The uptake is very slow, 1 mg in 36 years, and is consistent with an assumption that Al3+ taken up by the brain cannot be eliminated and is therefore accumulated. The possibility that Al3+ may cause or contribute to some specific diseases, most of them related to aging, is discussed with the proposed metabolic picture in mind.
mesh_terms: D008841:Actin Cytoskeleton / Q000187:drug effects; D000535:Aluminum / Q000378:metabolism* / Q000494:pharmacology / Q000633:toxicity; D000544:Alzheimer Disease / Q000209:etiology; D000690:Amyotrophic Lateral Sclerosis / Q000209:etiology; D000782:Aneuploidy; D000818:Animals; D001327:Autoimmune Diseases / Q000276:immunology; D001608:Beryllium / Q000378:metabolism; D001692:Biological Transport; D001842:Bone and Bones / Q000378:metabolism; D001921:Brain / Q000378:metabolism; D002412:Cations; D002455:Cell Division; D002477:Cells / Q000378:metabolism; D002857:Chromium / Q000378:metabolism; D003238:Connective Tissue / Q000378:metabolism; D003593:Cytoplasm / Q000378:metabolism; D004247:DNA / Q000378:metabolism; D004314:Down Syndrome / Q000209:etiology; D004660:Encephalitis / Q000209:etiology; D004912:Erythrocytes / Q000378:metabolism; D005243:Feces / Q000378:metabolism; D005708:Gallium / Q000494:pharmacology; D006801:Humans; D006967:Hypersensitivity / Q000276:immunology; D007111:Immunity, Cellular; D007204:Indium / Q000378:metabolism; D007408:Intestinal Absorption; D007413:Intestinal Mucosa / Q000378:metabolism; D008168:Lung / Q000378:metabolism; D008563:Membrane Lipids / Q000378:metabolism; D008870:Microtubules / Q000187:drug effects; D009136:Muscular Dystrophies / Q000209:etiology; D009630:Nondisjunction, Genetic / Q000187:drug effects; D010018:Osteomalacia / Q000209:etiology; D010300:Parkinson Disease / Q000209:etiology; D006435:Renal Dialysis / Q000009:adverse effects; D012538:Scandium / Q000378:metabolism; D014018:Tissue Distribution; D014168:Transferrin / Q000378:metabolism; D015019:Yttrium / Q000378:metabolism; D015040:Zirconium / Q000378:metabolism
chemical_list: D002412:Cations; D008563:Membrane Lipids; D014168:Transferrin; D007204:Indium; D002857:Chromium; D015019:Yttrium; D004247:DNA; D015040:Zirconium; D005708:Gallium; D000535:Aluminum; D001608:Beryllium; D012538:Scandium