Pituitary growth hormone suppression reduces resistin expression and enhances insulin effectiveness: Relationship with caloric restriction
- 作者：Takuya Chiba ; Haruyoshi Yamaza ; Toshimitsu Komatsu ; Masahiko Nakayama ; Satoshi Fujita ; Hiroko Hayashi ; Yoshikazu Higami ; Isao Shimokawa
- 关键词：Growth hormone ; IGF-I ; Calorie restriction ; Insulin sensitivity ; Adipokine
- 刊名：Experimental Gerontology
- 出版年：2008
- 期刊代码：99_05315565
- 类别：med
- 出版时间：June 2008
- 卷：43
- 期：6
- 页码：595-600
- 文件大小：204 K
摘要
Caloric restriction (CR) retards various age-dependent disorders, increases lifespan, and improves insulin activity in laboratory animals. Recently, adipocytes were found to act together as an active endocrine organ that produces various hormones called adipocytokines. The peripheral and central activities of these adipocytokines have been suggested to mediate the anti-aging effects of CR. Here, we tested this notion by analyzing the effect of CR and suppression of growth hormone/insulin-like growth factor-I (GH/IGF-I) axis on the expression of resistin, adiponectin, and adipsin genes by rat white adipose tissue (WAT). We found that CR and GH/IGF-I suppression markedly downregulated resistin gene expression. We also found plasma resistin levels correlated positively with pituitary GH mRNA expression levels. Our observations suggest that CR reduces resistin expression and increases insulin effectiveness in a GH/IGF-I-dependent manner. The beneficial effects of CR and GH/IGF-I suppression appear to be mediated, at least in part, by changes in glucose metabolism that result from reductions in plasma resistin levels.