Yamaguchi M
Department of Environmental Biochemistry, Shizuoka College of Pharmacy, Japan.
Mol Cell Endocrinol. 1989 Apr;62(2):313-8. doi: 10.1016/0303-7207(89)90019-1.
The effect of calcitonin (synthetic [Asu1,7]eel) on the exchangeable Ca2+ transport was investigated in isolated rat hepatocytes by measuring 45Ca2+ uptake. Calcitonin (CT) increased the uptake of Ca2+ with 74.3 pM giving a half-maximal effect. The action of CT was evident within 5 min after the hormone addition to the cells, and the increase in Ca2+ uptake was maintained during 60 min. The increase in Ca2+ uptake caused by CT was dependent on extracellular Ca2+ concentration. On the other hand, the activity of mitochondrial succinate dehydrogenase in hepatocytes was significantly increased by addition of CT (74.3 pM) to the cells in the presence of 1.3 mM Ca2+, while the hormonal effect was not seen in the absence of added Ca2+. The presence of Ca2+ ionophore A23187 (0.1 and 1.0 microM) abolished the increase in enzyme activity caused by CT addition to the cells. It is proposed that CT can increase the rate of uptake of exchangeable CA2+ by hepatocytes, and that the hormone causes the elevation of mitochondrial succinate dehydrogenase activity which is mediated through Ca2+.
通过测量45Ca2+摄取，研究了降钙素（合成的[Asu1,7]鳗鱼降钙素）对分离的大鼠肝细胞中可交换Ca2+转运的影响。降钙素（CT）增加了Ca2+的摄取，74.3 pM时产生半数最大效应。将激素添加到细胞后5分钟内，CT的作用就很明显，并且Ca2+摄取的增加在60分钟内持续存在。CT引起的Ca2+摄取增加依赖于细胞外Ca2+浓度。另一方面，在存在1.3 mM Ca2+的情况下，向细胞中添加CT（74.3 pM）可显著增加肝细胞中线粒体琥珀酸脱氢酶的活性，而在不添加Ca2+的情况下未观察到激素效应。Ca2+离子载体A23187（0.1和1.0 microM）的存在消除了向细胞中添加CT所引起的酶活性增加。有人提出，CT可以增加肝细胞对可交换CA2+的摄取速率，并且该激素会导致线粒体琥珀酸脱氢酶活性升高，这是通过Ca2+介导的。
