MDIA2004P4

P-4：Effect of chromium chloride GTF milk powder supplement on gene expression of insulin signaling molecules in KK/HlJ diabetic mice

Tong-Yuan Tai, Lee-Ming Chuang, Frank Chia-hung Mao

Division of Gerontology Research, National Health Research Institutes; Taipei, Taiwan Department of Internal Medicine, National Taiwan University Hospital; Taipei, Taiwan; Department of Veterinary Medicine, National Chung Hsing University; Tai-Chung, Taiwan

KK/HlJ type 2 diabetic mice model is equivalent to human type 2 diabetes because these mice are frequently associated with obesity, hyperinsulinemia, and hyperglycemia. There is evidence that the metabolic disturbances can be ameliorated after supplement of a chromium chloride GTF milk powder. In this study, two groups (each consisting of 6 mice) of 10 week-old male KK/HlJ mice were fed with a standard chow (Lab Diet 5001) supplement with or without 8% chromium chloride GTF-enriched milk powder for 6 weeks. There was no difference in the body weight (38.9+2.5 g for control vs. 38.5+1.9 g for GTF group). Intraperitoneal GTT revealed no significant reduction in glycemic excursion in GTF-treated group. However, there was a significant increase in insulin sensitivity by modified ITT. After overnight 18-hour fast, a fasting blood sample and tissues were obtained from the mice after decapitation. Fasting blood glucose concentrations were not significantly different between the two groups. However, the mean of insulin was significantly lower in GTF-treated group compared with control group (11.3+14.7U/ml vs. 98.0+91.2 U/ml, p<.05). Plasma adiponectin levels were not different between groups (22.3+4.9 g/ml for GTF group vs. 20.7+5.2 g/ml for control group). Studies of intracellular signaling molecules involved in insulin action revealed that the protein expression of insulin receptor was not changed in the liver and muscle between two groups of mice. However, the expression of the downstream signaling molecules including IRS-1 and CAP (equivalent to SORBS1 in human) was increased in the liver, skeletal muscle and testicular fat tissues of GTF-treated mice. These results suggest that improvement of glucose metabolism by supplement of the chromium chloride GTF milk powder might be partially explained by the up-regulation of the insulin signaling molecules in the KK/HlJ diabetic mice.