Yamauchi K, Hashizume K
Endocrinology. 1986 Jul;119(1):218-23. doi: 10.1210/endo-119-1-218.
Effects of glucagon on insulin action in rat epididymal adipocytes were studied in vitro. [125I]iodoinsulin binding to isolated adipocytes was inhibited by preincubation of the cells with isoproterenol, epinephrine, or glucagon. Fifty percent inhibition was observed with 2 X 10(-8) M glucagon, 10(-6) M isoproterenol, and 10(-7) M epinephrine. Maximal (90%) inhibition induced by glucagon was observed at 10(-6) M. In Scatchard analysis, [125I]iodoinsulin competition data generated curvilinear plots in buffer- and glucagon-treated cells. Pretreatment of the cells with (Bu)2cAMP reduced insulin binding activity. However, the simultaneous addition of (Bu)2cAMP with [125I]iodoinsulin did not produce the inhibition of the binding when the cells were not pretreated with the agent. cAMP level in the cells was increased by incubation with glucagon. 3-O-[Methyl-3H]methylglucose uptake by isolated adipocytes was inhibited by pretreatment of the cells with glucagon. These results suggest that glucagon regulates insulin action through decrease in insulin receptor activity, and that it is possible that the inhibition is mediated by cAMP production in adipocytes.
在体外研究了胰高血糖素对大鼠附睾脂肪细胞胰岛素作用的影响。用异丙肾上腺素、肾上腺素或胰高血糖素预孵育细胞可抑制[125I]碘胰岛素与分离的脂肪细胞的结合。2×10（-8）M胰高血糖素、10（-6）M异丙肾上腺素和10（-7）M肾上腺素可观察到50%的抑制作用。在10（-6）M时观察到胰高血糖素诱导的最大（90%）抑制作用。在Scatchard分析中，[125I]碘胰岛素竞争数据在缓冲液处理和胰高血糖素处理的细胞中产生曲线。用（Bu）2cAMP预处理细胞可降低胰岛素结合活性。然而，当细胞未用该试剂预处理时，（Bu）2cAMP与[125I]碘胰岛素同时添加不会产生结合抑制。用胰高血糖素孵育可增加细胞内的cAMP水平。用胰高血糖素预处理分离的脂肪细胞可抑制3-O-[甲基-3H]甲基葡萄糖摄取。这些结果表明，胰高血糖素通过降低胰岛素受体活性来调节胰岛素作用，并且这种抑制可能是由脂肪细胞中cAMP的产生介导的。
