目的 探讨高脂饮食诱导的胰岛素抵抗大鼠糖代谢及抵抗素、脂联素水平的变化。方法 采用大鼠扩展胰岛素钳夹和3-^3H标记葡萄糖示踪技术,估计高脂诱导胰岛素抵抗(IR)大鼠肝糖及外周组织糖代谢的变化,同时采用酶免法检测血浆抵抗素及脂联素水平。结果 高脂喂养组(HF组)大鼠基础血浆游离脂肪酸(FFA)水平明显增高。钳夹稳态时,HF组血浆胰岛素水平明显高于N组,差异有统计学意义(P〈0.01),FFA也明显高于N组,差异有统计学意义(P〈0.01)。HF组葡萄糖输注率(GIR)较N组减少38%,胰岛素介导的葡萄糖利用率(GRd)较N组亦明显减少21%。N组大鼠肝糖输出(HGP)明显抑制达71%,而在HF组胰岛素介导的HGP的抑制作用受到明显障碍(仅抑制30%)。钳夹结束时,N组血浆抵抗素水平与基础值相比明显降低,差异有统计学意义(P〈0.05),而HF组明显高于N组(P〈0.05)。两组血浆脂联素水平在钳夹后均明显下降差异有统计学意义(P〈0.05)。结论 高脂饮食诱导大鼠产生了外周和肝脏的IR。IR的形成可能与血浆FFA升高和在高胰岛素状态下较高的血浆抵抗素水平有关。
Objective To investigate the changes of glucose metabolism, plasma resistin and adiponectin levels in insulin-resistant rats induced by high-fat diet. Methods Changes of peripheral and hepatic glucose metabolism in awake rats were evaluated by hyperinsulinemic euglycemic clamp technique combined with 3-3H glucose as a tracer. And plasma resistin and adiponectin were detected by ELISA. Results In baseline, plasma free fatty acids (FFA) levels were increased in high-fat diet rats (HF) compared with normal chow diet rats (N). During clamp steady-state, plasma insulin and FFA levels were higher in HF group compared with control (P〈0.01). In HF group, the glucose infusion rate (GIR) and glucose disappearance rate (GRd) were reduced by 38% and 21%, respectively. And the insulin-mediated suppression of hepatic glucose production was up to 71% in N group, but it was impaired and only up to 30% in HF rats (P〈0.01). At the end of the clamp, plasma resistin levels were decreased in N group and lower than that in HF rats (P〈0.05). Howevre, plasma adiponectin levels were both decreased after clamp (P〈0.05). Conclusion High-fat diet induced peripheral and hepatic insulin resistance in rats. It might be associated with elevated FFA and higher plasma resistin levels during hyperinsulinemia.