Hosokawa Y, Yamaguchi K, Kohashi N, Kori Y, Ueda I
J Biochem. 1978 Aug;84(2):419-24. doi: 10.1093/oxfordjournals.jbchem.a132142.
The hepatic cysteine dioxygenase activity of rats was markedly decreased by the intraperitoneal administration of glucagon. The enzyme activity was also decreased by either dibutyryl cyclic AMP or theophylline. The prior administration of actinomycin D completely blocked the glucagon-mediated decrease of enzyme activity, while administrations of this inhibitor of protein synthesis after glucagon injection did not block the decrease of enzyme activity. A single administration of actinomycin D resulted in a slight increase of cysteine dioxygenase activity in the rat liver. On the other hand, the injection of cycloheximide resulted in a rapid decrease of the hepatic cysteine dioxygenase with a half-life of 2.5 h. The half-life of the enzyme in rat liver after glucagon administration was one hour. The administration of hydrocortisone or insulin had no effect on the glucagon-mediated decrease of cysteine dioxygenase of rat liver. The enzyme activity of alloxan diabetic rat liver was almost the same as that of the intact rat liver. The evidence obtained here suggests that enhancement of degradation or inactivation of cysteine dioxygenase is responsible for the glucagon-mediated decrease of the enzyme activity in rat liver.
通过腹腔注射胰高血糖素，大鼠肝脏中的半胱氨酸双加氧酶活性显著降低。二丁酰环磷腺苷或茶碱也可降低该酶活性。预先给予放线菌素D可完全阻断胰高血糖素介导的酶活性降低，而在注射胰高血糖素后给予这种蛋白质合成抑制剂则不能阻断酶活性的降低。单次给予放线菌素D会使大鼠肝脏中的半胱氨酸双加氧酶活性略有增加。另一方面，注射环己酰亚胺会导致肝脏半胱氨酸双加氧酶迅速降低，半衰期为2.5小时。给予胰高血糖素后，该酶在大鼠肝脏中的半衰期为1小时。给予氢化可的松或胰岛素对胰高血糖素介导的大鼠肝脏半胱氨酸双加氧酶活性降低没有影响。四氧嘧啶糖尿病大鼠肝脏的酶活性与完整大鼠肝脏的酶活性几乎相同。此处获得的证据表明，半胱氨酸双加氧酶降解或失活的增强是胰高血糖素介导的大鼠肝脏中该酶活性降低的原因。
