Resistin is a
protein secreted from adipose tissue that is thought to play a role in
insulin sensitivity. We examined the effects of
rosiglitazone and
metformin on the plasma
resistin levels in individuals with
type 2 diabetes mellitus. Patients with
type 2 diabetes mellitus who showed poor
glycemic control with
glimepiride (4 mg/d) were randomized to
rosiglitazone (4 mg/d) and
metformin (500 mg bid) treatment groups. All subjects continued
glimepiride treatment as well. The plasma concentrations of
resistin were measured at baseline and at 6 months of treatment for both groups. The anthropometric parameters, fasting plasma
glucose, HbA1c, total
cholesterol,
triglyceride,
high-density lipoprotein cholesterol,
free fatty acids, and
adiponectin concentrations were also measured. After 6 months of treatment, the reduction in plasma
glucose levels was similar between the 2 groups. There were no significant changes in the
lipid profiles of either group during the study period. The plasma
resistin levels decreased in the
rosiglitazone group (2.49 +/- 1.93 vs 1.95 +/- 1.59 ng/ml; P < .05) but increased in the
metformin group (2.61 +/- 1.69 vs 5.13 +/- 2.81 ng/ml; P < .05). The plasma
adiponectin concentrations were increased in the
rosiglitazone group (2.91 +/- 1.46 vs 4.23 +/- 1.77 microg/ml; P < .05) but were unchanged in the
metformin group. In summary,
rosiglitazone treatment decreased the plasma
resistin levels whereas
metformin treatment increased them in patients with
type 2 diabetes mellitus showing poor
glycemic control with sulfonylurea
therapy. These results suggest that the observed changes in plasma
resistin levels are not the consequences of improved
insulin resistance, nor are they consequences of
glycemic control. Considering the potential role of
resistin in
insulin resistance, decrease in
resistin levels may contribute to improving
insulin action with
rosiglitazone treatment.