Yamaguchi M, Momose K
Endocrinol Jpn. 1982 Oct;29(5):553-9. doi: 10.1507/endocrj1954.29.553.
The effect of calcitonin (CT) on hepatic glycogenolysis was investigated after a single subcutaneous administration of the hormone to intact rats. Administration of CT (porcine CT; 80 MRC mU/100 g BW) produced a significant decrease in glycogen content of the liver, and corresponding increases in phosphorylase a activity and calcium content of the particulate glycogen fraction in the liver. These alterations were observed with the dose of CT at physiological level. The removal of calcium by 1 mM EGTA treatment of the hepatic particulate glycogen caused a clear reduction in the increase in phosphorylase a activity produced by CT administration. Meanwhile, the enzyme activity in 1 mM EGTA-treated particulate glycogen of the liver in both control and CT (80 MRC mU/100 g BW)-treated rats was significantly enhanced by the addition of calcium ion (10 microM). Furthermore, a single intraperitoneal administration of calcium chloride (2.0 mg Ca/100 g BW) to intact rats produced a remarkable increase in phosphorylase a activity and calcium content of the hepatic glycogen particulate fraction. These results suggest that the promotion of hepatic glycogenolysis by CT administration may result from the increase in phosphorylase a activity mediated by cellular calcium.
给完整的大鼠单次皮下注射降钙素（CT）后，研究了其对肝糖原分解的影响。给予CT（猪CT；80 MRC mU/100 g体重）后，肝脏糖原含量显著降低，同时肝脏中磷酸化酶a活性以及颗粒状糖原部分的钙含量相应增加。在CT处于生理水平剂量时观察到了这些变化。用1 mM乙二醇双四乙酸（EGTA）处理肝脏颗粒状糖原以去除钙，可使CT给药所引起的磷酸化酶a活性增加明显降低。同时，在对照大鼠和经CT（80 MRC mU/100 g体重）处理的大鼠中，通过添加钙离子（10 microM）可显著增强1 mM EGTA处理的肝脏颗粒状糖原中的酶活性。此外，给完整的大鼠单次腹腔注射氯化钙（2.0 mg钙/100 g体重）可使肝脏糖原颗粒部分的磷酸化酶a活性和钙含量显著增加。这些结果表明，CT给药促进肝糖原分解可能是由细胞钙介导的磷酸化酶a活性增加所致。
