Gemba M, Yamamoto K
Jpn J Pharmacol. 1975 Jun;25(3):233-40. doi: 10.1254/jjp.25.233.
Effect of inorganic phosphate (4 X 10(-3) M) on Ca++-accumulation was examined in kidney cortex mitochondria. Ca++-accumulation of rat kidney cortex mitochondria was slightly influenced by inorganic phosphate. On the other hand, dog kidney cortex mitochondria did not accumulate calcium from the incubation medium until the inorganic phosphate had been added. Ca++-accumulation of rabbit kidney cortex mitochondria was markedly stimulated by inorganic phosphate. When ethacrynic acid was added to the reaction medium in the absence of inorganic phosphate, Ca++-accumulation of rat kidney cortex mitochondria was depressed and the decrease in calcium content of rabbit and dog kidney cortex mitochondria was enhanced. In the presence of inorganic phosphate, the inhibition of Ca++-accumulation by ethacrynic acid was observed only on dog kidney cortex mitochondria. Subsequently, the effect of inorganic phosphate (4 X 10(-4) M) and ethacrynic acid (1 X 10(-4) M on Ca++-ATPase was examined in kidney cortex mitochondria. The low concentration of inorganic phosphate (4 X 10(-4) M) activated Ca++-ATPase of kidney cortex mitochondria in all animal species. The greatest activation of Ca++-ATPase occurred in rabbits, but the activity of the enzyme was lower than that in rats and dogs. Inhibition of Ca++-ATPase by ethacrynic acid was depressed by the addition of inorganic phosphate in kidney cortex mitochondria of experimental animals. Ca++-accumulation may be regulated through the stimulating effect of inorganic phosphate and the inhibitory effect of ethacrynic acid on Ca++-ATPase in kidney cortex mitochondria. Species difference in ethacrynic acid effect on Ca++-accumulation in kidney cortex mitochondria of rats, rabbits and dogs is discussed.
在肾皮质线粒体中研究了无机磷酸盐（4×10⁻³M）对钙离子积累的影响。大鼠肾皮质线粒体的钙离子积累受到无机磷酸盐的轻微影响。另一方面，狗肾皮质线粒体在添加无机磷酸盐之前不会从孵育培养基中积累钙。无机磷酸盐显著刺激兔肾皮质线粒体的钙离子积累。当在无无机磷酸盐的反应介质中加入依他尼酸时，大鼠肾皮质线粒体的钙离子积累受到抑制，兔和狗肾皮质线粒体的钙含量下降增强。在有无机磷酸盐存在的情况下，仅在狗肾皮质线粒体中观察到依他尼酸对钙离子积累的抑制作用。随后，在肾皮质线粒体中研究了无机磷酸盐（4×10⁻⁴M）和依他尼酸（1×10⁻⁴M）对钙离子ATP酶的影响。低浓度的无机磷酸盐（4×10⁻⁴M）激活了所有动物物种肾皮质线粒体的钙离子ATP酶。钙离子ATP酶的最大激活发生在兔子身上，但该酶的活性低于大鼠和狗。在实验动物的肾皮质线粒体中，加入无机磷酸盐可抑制依他尼酸对钙离子ATP酶的抑制作用。钙离子积累可能通过无机磷酸盐的刺激作用和依他尼酸对肾皮质线粒体钙离子ATP酶的抑制作用来调节。讨论了依他尼酸对大鼠、兔子和狗肾皮质线粒体钙离子积累影响的物种差异。
