title: Effects of gallium and mercury ions on transport systems.
abstract: Mercury was previously shown to exert toxic effects by influencing ion channels and transporters in the kidney and brain. Gallium alloys were suggested as less toxic restorative materials. To compare the toxicity of gallium ions with those of mercury ions, we applied gallium nitrate Ga(NO3)3 (0.1-100 microM and mercuric chloride (HgCl2) (0.001-10 microM) to Xenopus oocytes expressing mammalian ion channels and transport proteins. Mercury (10 microM) inhibited the K+-channels ROMK and HERG, the phosphate transporter NaPi-3, the amino acid transporter rBAT, the cation transporter OCT-2, and the osmolyte transporter BGT. It activated the I(Ks)-channel but did not affect the Na+-channel ENaC, the anion channel NaPi-1, and the glucose transporter SGLT-1. Gallium was without significant effect on the channels and on SGLT1, NaPi-3, and rBAT, but inhibited BGT and OCT-2. In conclusion, both Hg2+ and Ga3+ may exert toxic effects on transport systems, which may partially explain their cytotoxic effects.
authors.affiliation: Department of Physiology I, University of Tuebingen, Germany.
authors.lastname: Moschèn
authors.forename: K
authors.initials: K
authors.lastname: Schweizer
authors.forename: C A
authors.initials: CA
authors.lastname: Wagner
authors.forename: J
authors.initials: J
authors.lastname: Geis-Gerstorfer
authors.forename: F
authors.initials: F
authors.lastname: Lang
mesh_terms: D026905:Amino Acid Transport Systems / Q000037:antagonists & inhibitors; D026923:Amino Acid Transport Systems, Basic; D000596:Amino Acids / Q000037:antagonists & inhibitors; D000704:Analysis of Variance; D000818:Animals; D001622:Betaine / Q000037:antagonists & inhibitors; D002352:Carrier Proteins / Q000037:antagonists & inhibitors / Q000187:drug effects*; D004268:DNA-Binding Proteins / Q000037:antagonists & inhibitors; D050485:GABA Plasma Membrane Transport Proteins; D005708:Gallium / Q000633:toxicity*; D005947:Glucose / Q000378:metabolism; D007473:Ion Channels / Q000187:drug effects*; D017136:Ion Transport / Q000187:drug effects; D008562:Membrane Glycoproteins / Q000037:antagonists & inhibitors / Q000187:drug effects; D008565:Membrane Proteins / Q000037:antagonists & inhibitors; D008627:Mercuric Chloride / Q000633:toxicity; D008628:Mercury / Q000633:toxicity*; D009004:Monosaccharide Transport Proteins / Q000187:drug effects; D009865:Oocytes / Q000187:drug effects; D028061:Phosphate Transport Proteins / Q000037:antagonists & inhibitors; D010710:Phosphates / Q000037:antagonists & inhibitors; D026902:Potassium Channel Blockers; D012964:Sodium / Q000378:metabolism; D015222:Sodium Channels / Q000187:drug effects; D051269:Sodium-Glucose Transporter 1; D050608:Sodium-Phosphate Cotransporter Proteins; D013223:Statistics as Topic; D027981:Symporters / Q000037:antagonists & inhibitors / Q000187:drug effects; D014157:Transcription Factors / Q000037:antagonists & inhibitors; D014981:Xenopus
chemical_list: D026905:Amino Acid Transport Systems; D026923:Amino Acid Transport Systems, Basic; D000596:Amino Acids; D002352:Carrier Proteins; D004268:DNA-Binding Proteins; D050485:GABA Plasma Membrane Transport Proteins; D007473:Ion Channels; D008562:Membrane Glycoproteins; D008565:Membrane Proteins; D009004:Monosaccharide Transport Proteins; D028061:Phosphate Transport Proteins; D010710:Phosphates; D026902:Potassium Channel Blockers; D015222:Sodium Channels; D051269:Sodium-Glucose Transporter 1; D050608:Sodium-Phosphate Cotransporter Proteins; D027981:Symporters; D014157:Transcription Factors; C072207:betaine plasma membrane transport proteins; D001622:Betaine; D008627:Mercuric Chloride; D012964:Sodium; D005708:Gallium; D008628:Mercury; D005947:Glucose; C027235:gallium nitrate