Effects of skyrin, a receptor-selective glucagon antagonist, in rat and human hepatocytes
Effects of skyrin, a receptor-selective glucagon antagonist, in rat and human hepatocytes
复制标题
DOI：
10.2337/diabetes.49.12.2079
复制
发表时间：
2000-12-01
期刊：
影响因子：
7.7
通讯作者：
Treadway, JL
中科院分区：
文献类型：
--
作者：
Parker, JC;McPherson, RK;Treadway, JL
肽胰高血糖素拮抗剂已显示在糖尿病模型中降低血糖水平（1-3），但鉴定小分子量胰高血糖素受体结合拮抗剂的尝试几乎没有成功。Skyrin是一种真菌二蒽醌，通过将胰高血糖素受体与大鼠肝膜中的腺苷酸环化酶活化解偶联而表现出功能性胰高血糖素拮抗作用（1）。我们已经检查了Skyrin对转染人胰高血糖素受体的细胞以及对分离的大鼠和人肝细胞的影响。所用skyrin分离自Talaromyces wortmanni American Type Culture Collection 10517。在大鼠肝细胞中，skyrin（30 μ mol/l）抑制胰高血糖素刺激的cAMP产生（53%）和葡萄糖输出（IC 50 56 μ mol/l）。这些参数对肾上腺素或胰高血糖素样肽1（GLP-1）刺激没有可检测到的影响，这证明了skyrin的选择性活性。还在人肝细胞的原代培养物中评价了Skyrin。与对胰高血糖素基本无反应的细胞系不同，原代人肝细胞在培养物中显示胰高血糖素依赖性cAMP产生14天（EC 50 10 nmol/l），Skyrin（10 μ mol/l）显著降低人肝细胞中胰高血糖素刺激的cAMP生成（55%）和糖原分解（27%），对胰高血糖素刺激的抑制是skyrin和oxyskyrin显示的特异性性质，但不被其他二蒽醌共享。Skyrin是第一个被证明干扰胰高血糖素与腺苷酸环化酶偶联的小分子量非肽类药物，与胰高血糖素受体结合无关。本研究中提供的数据表明，人胰高血糖素受体与cAMP产生的功能性解偶联导致代谢效应，可减少肝细胞葡萄糖产生，从而缓解糖尿病高血糖症。
Peptidic glucagon antagonists have been shown to lower blood glucose levels in diabetic models (1-3), but attempts to identify small molecular weight glucagon receptor-binding antagonists have met with little success. Skyrin, a fungal bisanthroquinone, exhibits functional glucagon antagonism by uncoupling the glucagon receptor from adenylate cyclase activation in rat Liver membranes (1), We have examined the effects of skyrin on cells transfected with the human glucagon receptor and on isolated rat and human hepatocytes. The skyrin used was isolated from Talaromyces wortmanni American Type Culture Collection 10517, In rat hepatocytes, skyrin (30 mu mol/l) inhibited glucagon-stimulated cAMP production (53%) and glucose output (IC50 56 mu mol/l). There was no detectable effect on epinephrine or glucagon-like peptide 1 (GLP-1) stimulation of these parameters, which demonstrates skyrin's selective activity. Skyrin was also evaluated in primary cultures of human hepatocytes, Unlike cell lines, which are largely unresponsive to glucagon, primary human hepatocytes exhibited glucagon-dependent cAMP production for 14 days in culture (EC50 10 nmol/l), Skyrin (10 mu mol/l) markedly reduced glucagon-stimulated cAMP production (55%) and glycogenolysis (27%) in human hepatocytes, The inhibition of glucagon stimulation was a specific property displayed by skyrin and oxyskyrin but not shared by other bisanthroquinones, Skyrin is the first small molecular weight nonpeptidic agent demonstrated to interfere with the coupling of glucagon to adenylate cyclase independent of binding to the glucagon receptor. The data presented in this study indicate that functional uncoupling of the human glucagon receptor from cAMP production results in metabolic effects that could reduce hepatocyte glucose production and hence alleviate diabetic hyperglycemia.