Yamaza Haruyoshi, Komatsu Toshimitsu, To Kazuo, Toyama Hiroaki, Chiba Takuya, Higami Yoshikazu, Shimokawa Isao
Pathology & Gerontology, Nagasaki University Graduate School of Biomedical Sciences, 12-4 Sakamoto 1-chome, Nagasaki City 852-8523, Japan.
J Gerontol A Biol Sci Med Sci. 2007 Jan;62(1):27-33. doi: 10.1093/gerona/62.1.27.
Insulin-like growth factor (IGF)-1 signaling might partly mediate effects of caloric restriction (CR), an experimental intervention for increasing longevity in mammals. The present study evaluated effects of recombinant human (rh)IGF-1 infusion on adipokine levels in CR and transgenic (Tg) dwarf rats with the reduced growth hormone-IGF-1 axis, which shared similar body weight and food intake. At 9 months of age, each rat received a continuous infusion of rhIGF-1 for 14 days, and rats received an injection of glucose after overnight fasting. Infusion of rhIGF-1 had metabolic effects in all rat groups although it did not affect insulin sensitivity in any of the groups. In addition, plasma adiponectin was decreased to the control group levels and plasma leptin was further reduced in CR and Tg rats. The similarity of phenotypes and adipokine responses to rhIGF-1 between CR and Tg rats supports a role for reduced IGF-1 signaling in the CR effect.
胰岛素样生长因子（IGF）-1信号通路可能部分介导了热量限制（CR）的作用，热量限制是一种用于延长哺乳动物寿命的实验性干预措施。本研究评估了重组人（rh）IGF-1输注对CR大鼠和生长激素-IGF-1轴降低的转基因（Tg）侏儒大鼠脂肪因子水平的影响，这两类大鼠体重和食物摄入量相似。9月龄时，每只大鼠连续输注rhIGF-1 14天，大鼠过夜禁食后注射葡萄糖。rhIGF-1输注在所有大鼠组中均有代谢作用，尽管它对任何一组的胰岛素敏感性均无影响。此外，CR大鼠和Tg大鼠的血浆脂联素降至对照组水平，血浆瘦素进一步降低。CR大鼠和Tg大鼠之间表型及对rhIGF-1的脂肪因子反应的相似性支持了IGF-1信号通路减弱在CR效应中的作用。
