Plasma asymmetric dimethylarginine concentrations are elevated in obese insulin-resistant women and fall with weight loss.

CONTEXT

Plasma asymmetric dimethylarginine (ADMA) concentrations are higher in apparently healthy, insulin-resistant (IR) individuals and decrease in response to thiazolidenedione treatment.

OBJECTIVE

The objective of the study was to determine whether ADMA concentrations would also fall when insulin sensitivity is enhanced with weight loss in obese individuals. DESIGN/SETTING/PATIENTS/INTERVENTION: Twenty obese women classified as IR or insulin sensitive (IS) on the basis of their steady-state plasma glucose (SSPG) concentration during the insulin suppression test underwent 12 wk of dietary weight loss.

OUTCOME MEASURES

Plasma glucose, insulin, and ADMA were measured at baseline and after weight loss; change in insulin resistance was quantified by repeating the SSPG after the dietary intervention.

RESULTS

Although weight loss was similar in the two groups, significant improvements in SSPG, glucose, and insulin concentrations were confined to the IR group. Baseline plasma ADMA concentrations (mean +/- sd) were higher in IR subjects (1.69 +/- 0.44 vs. 1.18 +/- 0.45 micromol/liter, P = 0.02) and decreased to 1.20 +/- 0.22 micromol/liter (P < 0.001) with weight loss. In contrast, ADMA levels did not change with a similar extent of weight loss in the IS group.

CONCLUSION

Plasma ADMA levels are higher in obese, IR women than in equally obese, IS women and decrease in response to weight loss when associated with enhancement of insulin sensitivity.