期刊名称：Journal of Nutritional Science and Vitaminology
印刷版ISSN：0301-4800
电子版ISSN：1881-7742
出版年度：2012
卷号：58
期号：6
页码：408-414
DOI：10.3177/jnsv.58.408
出版社：Center for Academic Publications Japan
摘要：Coffee has an anti-diabetic effect, specifically the amelioration of both hyperglycemia and insulin resistance, in KK- Ay mice, a type 2 diabetes animal model. To investigate coffee's effect on insulin signaling in liver, skeletal muscle, and adipose tissue (epididymal fat), we assayed the tyrosine phosphorylation of insulin receptor (IR) and serine phosphorylation of Akt. In Expt. 1, we assayed insulin signaling under nonfasting conditions in KK- Ay mice that ingested water or coffee for 4 wk. Coffee ingestion ameliorated the development of hyperglycemia but did not affect insulin signaling in liver or skeletal muscle under such conditions. In Expt. 2, we assayed insulin signaling under basal and insulin-stimulated conditions in KK- Ay mice that ingested water or coffee for 3 wk. The levels of tyrosine phosphorylation of insulin receptor in response to insulin injection in insulin-sensitive tissues were not different between mice that drank water and those that drank coffee. Coffee ingestion significantly increased the insulin-induced serine phosphorylation of Akt in liver and skeletal muscle, but not in epididymal fat, of KK- Ay mice. Our results also indicated that coffee ingestion may contribute to the improvement of insulin resistance and hyperglycemia in KK- Ay mice via the activation of Akt in insulin signaling in liver and skeletal muscle.
