The effect of rosiglitazone on insulin sensitivity and mid-thigh low-density muscle in patients with Type 2 diabetes.

AIMS: We examined the effect of rosiglitazone on insulin sensitivity, abdominal fat and mid-thigh intramuscular fat distribution, and plasma concentrations of adipocytokines in patients with Type 2 diabetes. METHODS: Rosiglitazone was administered at a daily dose of 4 mg to 42 Type 2 diabetes patients [age 32-70 years, body mass index (BMI) 17.5-32.6 kg/m(2), 15 women, 27 men] for 12 weeks. Various anthropometric and metabolic profiles, plasma adiponectin, leptin, and resistin levels were measured, and insulin resistance was calculated from the short insulin tolerance test. Body fat composition was assessed by computed tomography. RESULTS: Twelve weeks' rosiglitazone treatment resulted in improved insulin resistance despite increases in body weight and BMI. There was a significant decrease in abdominal visceral adipose tissue area (145 +/- 65.6 vs. 129 +/- 73.1 cm(2), P = 0.049). Mid-thigh low-density muscle area (TLDMA) increased from 23 +/- 9.6 to 26 +/- 8.2 cm(2) (P = 0.009). There were significant changes in plasma adipocytokines, but they were not significantly correlated with changes in insulin resistance. CONCLUSIONS: Rosiglitazone treatment resulted in an improvement of insulin responsiveness in Type 2 diabetic subjects, which was associated with the redistribution of visceral and subcutaneous adipose tissue, an increase in TLDMA, and changes in serum adipocytokine levels. Further studies are needed to elucidate the insulin sensitizing mechanism of rosiglitazone on peripheral skeletal muscles.