Chromium picolinate supplementation improves insulin sensitivity in Goto-Kakizaki diabetic rats

Chromium picolinate (CrP) supplementation has been studied as a potential therapy of insulin resistance and lipid abnormalities. There have been some reports involving chromium supplementation in patients with diabetes, but the results are varied. The present study was conducted to assess the effects of CrP on insulin sensitivity and body weight in Goto-Kakizaki (GK) diabetic rats. We supplemented normal Sprague-Dawley (SD) rats and GK diabetic rats with supplemental CrP, 100 mg/kg/day once a day for 4 weeks. In the normal SD rats, the mean body weight of the control group increased by 50.5%, whereas that of the CrP-treated group increased by 65.9% (P < 0.05 vs control). Similarly, in the diabetic GK rats, CrP supplementation showed increased weight gain compared to the control group (133.4% vs 119.6% of the baseline weight, P < 0.01). Glucose tolerance tests (GTT) [ip injection of glucose; 2 g/kg] and insulin sensitivity tests [SQ injection of insulin (5 U/kg) plus ip injection of glucose (30 min after insulin injection)] were conducted. During insulin sensitivity tests at the end of treatment, the glucose levels were significantly lower in CrP-treated rats compared with the control rats (AUC0-->120; 113.1 +/- 32.0 vs 170.5 +/- 49.0 mg-min/mL, P < 0.05). During GTTs, the glucose levels and insulin concentrations in the CrP-treated rats were not different from those in the control rats. The results of these studies suggest that CrP supplementation in GK diabetic rats leads to increase of weight gain and improvement of insulin sensitivity. This raises the possibility that CrP supplementation can be considered to improve carbohydrate metabolism in patients with type 2 diabetes mellitus.