Evidence of Daytime Variation of Asymmetric Dimethylarginine: An Intervention Study with Rosiglitazon in Type 2 Diabetes

Background: Asymmetric dimethylarginine (ADMA) has in some, but not all studies been associated with insulin resistance (IR). We wanted to challenge the hypothesis that plasma ADMA levels are associated with IR in an intervention study using an insulin sensitizing drug. Another aim of the study was to study daytime ADMA variation and if food intake influence ADMA concentration. Methods: Nine patients with diet treated type 2 diabetes were investigated with daytime profiles of ADMA (8 am-5 pm) before and during treatment with rosiglitazone for 8 weeks. A control group matched for age and sex underwent a similar investigation at baseline. Results: After treatment with rosiglitazone, ADMA (0.630.64 mmol/L; p=0.26) and homocysteine (10.3 -10.6 mol/L; p=0.61) concentrations did not change. Postprandial (10 am – 5 pm) ADMA concentrations were 10% higher than fasting morning levels (p=0.006) and this difference was similar for controls and diabetes patients both pre and post treatment with rosiglitazone. Conclusions: Treatment with rosiglitazone aiming to improve insulin sensitivity did not affect ADMA concentration in type 2 diabetes patients. The ADMA daytime variation and the relation to food intake appear to be a novel finding and should be considered in future studies.