Pires Rogério C, Souza Eder E, Vanzela Emerielle C, Ribeiro Rosane A, Silva-Santos Júnia C, Carneiro Everardo M, Boschero Antonio C, Amaral Maria Esméria C
a Centro Universitário Hermínio Ometto, Programa de Pós Graduação em Ciências Biomédicas, FHO/UNIARARAS, Araras/SP.
Appl Physiol Nutr Metab. 2014 Aug;39(8):895-901. doi: 10.1139/apnm-2013-0520. Epub 2014 Feb 21.
The occurrence of metabolic disorders, such as diabetes, obesity, atherosclerosis, and hypertension, increases with age. Inappropriate food intake, when combined with genetic and hormonal factors, can trigger the occurrence of these diseases in aged organisms. This study investigated whether short-term calorie restriction (CR; 40% of the intake of control animals (CTL) for 21 days) benefits 1-year-old (CR1yr) and 2-year-old (CR2yr) Wistar rats, with regard to insulin secretion and action. Plasma insulin and the insulin secreted by isolated islets were measured with radioimmunoassay, and the insulin sensitivity of peripheral tissues was assessed with the intraperitoneal glucose tolerance test (IPGTT), intraperitoneal insulin tolerance test, and hepatic and muscle adenosine monophosphate-activated protein kinase (AMPK) phosphorylation measurements. Body weight, epididymal fat pad, epididymal fat pad/body weight index, plasma glucose, and insulin were lower in the CR1yr than in the control (CTL1yr) rats. Serum cholesterol, triglycerides, and protein, as well as hepatic and muscle glycogen content, were similar between the CR and CTL groups. The IPGTT was higher in CR2yr and CTL2yr rats than in CR1yr and CTL1yr rats, and insulin sensitivity was higher in CR1yr and CR2yr rats than in their respective CTLs. This was associated with an increase in hepatic and muscle AMPK phosphorylation. No differences in glucose-induced insulin secretion in the isolated islets were observed between CRs and their respective CTL rats. In conclusion, short-term calorie restriction provoked more severe alterations in CR1yr than CR2yr rats. The normoglycemia observed in both CR groups seems to be due to an increase in insulin sensitivity, with the involvement of liver and muscle AMPK.
代谢紊乱如糖尿病、肥胖症、动脉粥样硬化和高血压的发生率会随着年龄增长而增加。不当的食物摄入，若与遗传和激素因素相结合，会引发老年生物体中这些疾病的发生。本研究调查了短期热量限制（CR；21天内摄入量为对照动物（CTL）的40%）对1岁（CR1yr）和2岁（CR2yr）Wistar大鼠胰岛素分泌和作用方面是否有益。采用放射免疫分析法测定血浆胰岛素和分离胰岛分泌的胰岛素，并通过腹腔葡萄糖耐量试验（IPGTT）、腹腔胰岛素耐量试验以及肝脏和肌肉中腺苷单磷酸激活蛋白激酶（AMPK）磷酸化测量来评估外周组织的胰岛素敏感性。CR1yr大鼠的体重、附睾脂肪垫、附睾脂肪垫/体重指数、血浆葡萄糖和胰岛素均低于对照（CTL1yr）大鼠。CR组和CTL组之间的血清胆固醇、甘油三酯和蛋白质以及肝脏和肌肉糖原含量相似。CR2yr和CTL2yr大鼠的IPGTT高于CR1yr和CTL1yr大鼠，且CR1yr和CR2yr大鼠的胰岛素敏感性高于各自的CTL组。这与肝脏和肌肉中AMPK磷酸化增加有关。在CR组及其各自的CTL大鼠之间，未观察到分离胰岛中葡萄糖诱导的胰岛素分泌有差异。总之，短期热量限制对CR1yr大鼠造成的改变比CR2yr大鼠更严重。两个CR组中观察到的血糖正常似乎归因于胰岛素敏感性增加，且涉及肝脏和肌肉中的AMPK。
