Kleineke J, Söling H D
J Biol Chem. 1985 Jan 25;260(2):1040-5.
A nondisruptive technique developed by Bellomo et al. (Bellomo, G., Jewell, S. A., Thor, H., and Orrenius, S. (1982) Proc. Natl. Acad. Sci. U.S.A. 79, 6842-6846) has been used to examine the distribution of calcium ions between mitochondrial and extramitochondrial compartments in the perfused rat liver. The amount of calcium released by the uncoupler 2,4-dinitrophenol from the mitochondrial compartment was 19 +/- 2 nmol X g-1, wet weight, which is equivalent to a total calcium concentration of 3.5 X 10(-4) M in the mitochondria and is by several orders of magnitude smaller than the concentration thought to be present in these organelles. The amount of calcium released from the liver in the presence of the divalent cation ionophore A 23187 was 96 +/- 7 nmol X g-1, wet weight, which is of the same order of magnitude as the amount released by the calcium-dependent hormone vasopressin (97 +/- 11 nmol X g-1, wet weight). Experiments with different sequential combinations of hormone with uncoupler or ionophore reveal that in the perfused liver, in contrast to isolated hepatocytes or isolated mitochondria, the amount of calcium attributable to the mitochondria is too small to account for the calcium released during hormonal stimulation. Consequently extramitochondrial calcium stores are the main source of cellular calcium mobilized under this condition. In addition these findings imply that in the liver several mitochondrial enzymes, e.g. alpha-oxoglutarate dehydrogenase, can be effectively regulated by calcium and that the role of mitochondria in buffering the cytosolic free calcium in vivo has to be reconsidered.
贝洛莫等人（贝洛莫，G.，朱厄尔，S. A.，索尔，H.，和奥雷纽斯，S.（1982年）《美国国家科学院院刊》79，6842 - 6846）开发的一种非破坏性技术已被用于研究灌注大鼠肝脏中线粒体和线粒体外区室之间钙离子的分布。解偶联剂2,4 - 二硝基苯酚从线粒体区室释放的钙量为19±2 nmol×g⁻¹湿重，这相当于线粒体中总钙浓度为3.5×10⁻⁴ M，比认为存在于这些细胞器中的浓度小几个数量级。在二价阳离子载体A 23187存在下从肝脏释放的钙量为96±7 nmol×g⁻¹湿重，这与钙依赖性激素血管加压素释放的量（97±11 nmol×g⁻¹湿重）处于同一数量级。用激素与解偶联剂或载体的不同顺序组合进行的实验表明，在灌注肝脏中，与分离的肝细胞或分离的线粒体不同，可归因于线粒体的钙量太小，无法解释激素刺激期间释放的钙。因此，线粒体外钙储存是在此条件下动员的细胞钙的主要来源。此外，这些发现意味着在肝脏中，几种线粒体酶，例如α - 酮戊二酸脱氢酶，可以被钙有效调节，并且必须重新考虑线粒体在体内缓冲细胞质游离钙中的作用。
