title: Comparative effects of the Roundup and glyphosate on mitochondrial oxidative phosphorylation.
abstract: The potential toxicity of the herbicide Roundup and its fundamental substance (glyphosate) was tested in bioenergetic functions of isolated rat liver mitochondria. Roundup stimulates succinate-supported respiration twice, with simultaneous collapse of transmembrane electrical potential, while glyphosate used in the same concentrations does not induce any significant effect. Additionally, Roundup depresses state 3 respiration by about 40%, at 15 mM, whereas uncoupled respiration in the presence of FCCP is depressed by about 50%. Depression of uncoupled respiratory activity is mediated through partial inhibition of mitochondrial complexes II and III, but not of complex IV. The phosphorylative system was affected by both a direct and an indirect effect on the F0F1 ATPase activity. The addition of uncoupled concentrations of Roundup to Ca2+-loaded mitochondria treated with Ruthenium Red resulted in non-specific membrane permeabilization, as evidenced by mitochondrial swelling in isosmotic sucrose medium. Therefore, the uncoupling of oxidative phosphorylation is also related to the non-specific membrane permeabilization induced by Roundup. Glyphosate alone does not show any relevant effect on the mitochondrial bioenergetics, in opposition to Roundup formulation products. The differences in the toxicity observed could be either attributed to some products of Roundup or to a synergic effect of glyphosate and formulation products. Bearing in mind that mitochondria is provided with a variety of bioenergetic functions mandatory for the regulation of intracellular aerobic energy production and electrolyte homeostasis, these results question the safety of Roundup on animal health.
authors.affiliation: Departamento de Química, Universidade de Trás-os-Montes e Alto Douro, 5001 Vila Real, Portugal. fpeixoto@utad.pt
authors.forename: Francisco
authors.initials: F
authors.lastname: Peixoto
mesh_terms: D000244:Adenosine Diphosphate / Q000494:pharmacology; D000251:Adenosine Triphosphatases / Q000378:metabolism; D000818:Animals; D004357:Drug Synergism; D003576:Electron Transport Complex IV / Q000378:metabolism; D005998:Glycine / Q000031:analogs & derivatives* / Q000633:toxicity; D006540:Herbicides / Q000633:toxicity*; D066298:In Vitro Techniques; D008564:Membrane Potentials / Q000187:drug effects; D008930:Mitochondria, Liver / Q000187:drug effects* / Q000201:enzymology / Q000502:physiology; D025261:Mitochondrial Proton-Translocating ATPases / Q000378:metabolism; D008933:Mitochondrial Swelling / Q000187:drug effects; D010085:Oxidative Phosphorylation / Q000187:drug effects*; D051381:Rats; D017208:Rats, Wistar; D013384:Succinate Cytochrome c Oxidoreductase / Q000378:metabolism; D013385:Succinate Dehydrogenase / Q000378:metabolism; D000097797:Glyphosate
chemical_list: D000244:Adenosine Diphosphate; D000251:Adenosine Triphosphatases; D003576:Electron Transport Complex IV; D005998:Glycine; D006540:Herbicides; D025261:Mitochondrial Proton-Translocating ATPases; D013384:Succinate Cytochrome c Oxidoreductase; D013385:Succinate Dehydrogenase; D000097797:Glyphosate