Mitochondrial Ca2+ transport in lean and genetically obese (ob/ob) mice.
Isolated mitochondria from liver or brown adipose tissue of obese ob/ob mice demonstrated increased rates of Ca2+ uptake and release compared with those of lean mice. This enhanced transport activity was not found in mitochondria from kidney or skeletal muscle. Respiration-induced membrane potential was the same in mitochondria from lean and ob/ob mice. It is therefore concluded that the increased Ca2+ uptake rates reflect an activation of the Ca2+ uniporter rather than a change in the electrophoretic driving force. As mitochondria from pre-obese ob/ob mice did not show elevated rates of Ca2+ transport, the activated transport in the obese animals was thus a consequence of the state of obesity rather than being a direct effect of the ob/ob genotype. It is suggested that the enhanced activity of the Ca2+-transport pathways in liver and brown adipose tissue may alter metabolic functions in these tissues by modifying cytoplasmic or intramitochondrial Ca2+ concentrations.
D002001:Adipose Tissue, Brown / Q000378:metabolism*; D000818:Animals; D001692:Biological Transport; D002118:Calcium / Q000378:metabolism*; D003080:Cold Temperature; D005260:Female; D066298:In Vitro Techniques; D007425:Intracellular Membranes / Q000378:metabolism; D007668:Kidney / Q000378:metabolism; D007700:Kinetics; D008564:Membrane Potentials; D051379:Mice; D008820:Mice, Obese; D008928:Mitochondria / Q000378:metabolism*; D008930:Mitochondria, Liver / Q000378:metabolism*; D008931:Mitochondria, Muscle / Q000378:metabolism; D009765:Obesity / Q000378:metabolism*
D002118:Calcium