作者:Kinuyo Matsumoto、Shuhei Yamamoto、Yutaka Yoshikawa、Matsumi Doe、Yoshitane Kojima、Hiromu Sakurai、Hiroko Hashimoto、Naemi M. Kajiwara
DOI:10.1246/bcsj.78.1077
日期:2005.6
The insulinomimetic activity of zinc(II) complexes Zn(gln-m)2 and Zn(gln-e)2, respectively, with l-γ-glutamyl-methylamide (gln-m) and -ethylamide (theanine: gln-e), components of green tea, were compared to that of Zn(gln)2 with l-glutamine (gln) in an in vitro study using isolated rodent adipocytes treated with epinephrine in the presence of glucose, expressed as the IC50 value (50% inhibition concentration) of free fatty acids (FFA) released from fat cells. The former were found to have higher inslinomimetic activity than that of the latter. The IC50 values of the former were 0.61 and 0.56, respectively. Then, the anti-diabetic activity of a zinc(II) complex, Zn(gln-e)2, was examined in an in vivo experiment on KK-Ay mice, model animals of type-2 DM, by the intraperitoneal (ip) injection of 3–4 mg Zn/kg b.w./day for 13 days. The blood-glucose level of a group treated with a Zn complex, Zn(gln-e)2, decreased significantly after 13 days compared to those of non-treated and gln-e treated groups. The serum concentrations of triglyceride (TG) and HbA1c decreased significantly in Zn(gln-e)2 treated KK-Ay mice compared to those of the gln-e treated group, respectively. Furthermore, the improvement in glucose tolerance was confirmed by an oral glucose tolerance test.
在利用离体啮齿动物脂肪细胞处理肾上腺素的体外研究中,将锌(II)配合物 Zn(gln-m)2 和 Zn(gln-e)2分别与 l-γ-谷氨酰甲酰胺(gln-m)和乙酰胺(茶氨酸)的胰岛素模拟活性进行了比较:在一项使用分离的啮齿动物脂肪细胞进行的体外研究中,以脂肪细胞释放游离脂肪酸(FFA)的 IC50 值(50% 抑制浓度)表示,对绿茶成分 Zn(gln)2 与 l-谷氨酰胺(gln)进行了比较。结果发现,前者的胰岛素模拟活性高于后者。前者的 IC50 值分别为 0.61 和 0.56。然后,在 2 型糖尿病模型动物 KK-Ay 小鼠的体内实验中,通过腹腔注射(ip)3-4 毫克锌/千克体重/天,持续 13 天,检测了锌(II)复合物 Zn(gln-e)2 的抗糖尿病活性。13 天后,用锌复合物 Zn(gln-e)2 治疗组的血糖水平比未治疗组和用 gln-e 治疗组的血糖水平显著下降。经 Zn(gln-e)2 处理的 KK-Ay 小鼠血清中甘油三酯(TG)和 HbA1c 的浓度分别比经 gln-e 处理的组明显降低。此外,口服葡萄糖耐量试验也证实了葡萄糖耐量的改善。