大鼠甲状腺功能减退不会降低线粒体的ADP/O和H+/O比率。
Hypothyroidism in rats does not lower mitochondrial ADP/O and H+/O ratios.
作者信息
Hafner R P, Brand M D
机构信息
Department of Biochemistry, University of Cambridge, U.K.
出版信息
Biochem J. 1988 Mar 1;250(2):477-84. doi: 10.1042/bj2500477.
We investigated reports that mitochondria isolated from hypothyroid rats have decreased ADP/O and H+/O ratios. We observed no decrease in the H+/O ratio in mitochondria from hypothyroid rats, in the presence of either 2% (w/v) fatty-acid-free bovine serum albumin or 100 nM free Ca2+. The ADP/O ratio in mitochondria isolated from hypothyroid rats in the presence of 2% fatty-acid-free bovine serum albumin was measured. Under normal experimental conditions we found no decrease in the ADP/O ratio, relative to that measured for littermate controls. At the low concentrations of mitochondrial protein used in the previously reported studies, the ADP/O ratio of mitochondria from hypothyroid rats was decreased, whereas that for control rats was only slightly decreased. The difference between the ADP/O ratios measured for mitochondria form hypothyroid rats and from control rats under these conditions was eliminated by inhibition of endogenous adenylate kinase. We suggest that the lowering of the apparent ADP/O ratio in mitochondria from hypothyroid rats at low concentrations of mitochondrial protein is an experimental artefact resulting from the breakdown of ADP to AMP.
我们对有关从甲状腺功能减退大鼠分离出的线粒体的ADP/O和H⁺/O比率降低的报道进行了研究。在存在2%（w/v）无脂肪酸牛血清白蛋白或100 nM游离Ca²⁺的情况下，我们未观察到甲状腺功能减退大鼠线粒体的H⁺/O比率降低。测定了在存在2%无脂肪酸牛血清白蛋白的情况下从甲状腺功能减退大鼠分离出的线粒体的ADP/O比率。在正常实验条件下，相对于同窝对照所测的ADP/O比率，我们未发现其降低。在先前报道的研究中所使用的低线粒体蛋白浓度下，甲状腺功能减退大鼠线粒体的ADP/O比率降低，而对照大鼠的仅略有降低。通过抑制内源性腺苷酸激酶，消除了在这些条件下甲状腺功能减退大鼠和对照大鼠线粒体所测ADP/O比率之间的差异。我们认为，在低线粒体蛋白浓度下甲状腺功能减退大鼠线粒体中表观ADP/O比率的降低是由ADP分解为AMP导致的实验假象。
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