Myers S R, Diamond M P, Adkins-Marshall B A, Williams P E, Stinsen R, Cherrington A D
Department of Molecular Physiology, Vanderbilt University School of Medicine, Nashville, TN 37232.
Metabolism. 1991 Jan;40(1):66-71. doi: 10.1016/0026-0495(91)90194-2.
The aim of this study was to examine the influence of small changes in glucagon on hepatic glucose production during a euglycemic, hyperinsulinemic clamp. During 1.0 mU/kg.min insulin infusion, euglycemia was maintained by glucose infusion and glucagon was infused at various rates so as to cause plasma glucagon levels to increase, decrease, or remain unchanged. Changes in glucagon were found to be positively associated with changes in glucose production and inversely related to the degree of suppression of tracer or arteriovenous difference determined endogenous glucose production. Thus, animals in which the glucagon levels increased, appeared to have decreased hepatic insulin sensitivity, while animals in which glucagon levels decreased, appeared to have increased insulin sensitivity. In conclusion, since glucagon often declines during a euglycemic hyperinsulinemic clamp, and since small changes in glucagon can have marked effects on the suppression of hepatic glucose output even in the presence of high insulin levels, changes in glucagon should be considered when conclusions regarding hepatic insulin sensitivity are being drawn.
本研究的目的是在正常血糖、高胰岛素钳夹期间，检测胰高血糖素的微小变化对肝脏葡萄糖生成的影响。在以1.0 mU/kg·min的速率输注胰岛素期间，通过输注葡萄糖维持正常血糖水平，并以不同速率输注胰高血糖素，以使血浆胰高血糖素水平升高、降低或保持不变。发现胰高血糖素的变化与葡萄糖生成的变化呈正相关，与示踪剂或动静脉差值所测定的内源性葡萄糖生成的抑制程度呈负相关。因此，胰高血糖素水平升高的动物，肝脏胰岛素敏感性似乎降低；而胰高血糖素水平降低的动物，胰岛素敏感性似乎升高。总之，由于在正常血糖高胰岛素钳夹期间胰高血糖素常下降，且即使在高胰岛素水平存在的情况下，胰高血糖素的微小变化也可对肝脏葡萄糖输出的抑制产生显著影响，因此在得出关于肝脏胰岛素敏感性的结论时，应考虑胰高血糖素的变化。
