Influences of levodopa on adipose tissue and skeletal muscle metabolism in patients with idiopathic Parkinson's disease

OBJECTIVE: The substantial weight loss in Parkinson's patients may be related to direct influences of levodopa treatment on fat mobilization/oxidation. We assessed systemic and local metabolic responses to levodopa/benserazide in patients with idiopathic Parkinson's disease. METHODS: We studied 10 Parkinson's disease patients and examined adipose tissue and skeletal muscle metabolism directly with microdialysis. We monitored dialysate concentrations of ethanol, glucose, lactate, pyruvate, and glycerol to assess tissue blood flow and metabolism before and after levodopa/benserazide intake. We also conducted in vitro studies on adipocytes from healthy women. RESULTS: Levodopa/benserazide increased serum levodopa, 3,4-dihydroxyphenylacetic acid (DOPAC), and norepinephrine (P < 0.01). Serum adipose tissue and skeletal muscle glycerol did not change or decreased. Adipose tissue glycerol was inversely correlated with serum levodopa concentrations (P < 0.05). In isolated adipocytes, levodopa attenuated isoproterenol-induced glycerol release (P < 0.05). CONCLUSION: Levodopa/benserazide elicits pronounced metabolic changes in both adipose tissue and skeletal muscle with a switch from lipid to carbohydrate metabolism. In adipose tissue, levodopa/benserazide failed to activate lipolysis. Therefore, we suggest that levodopa/benserazide does not induce fat wasting through direct and acute influences on adipose tissue metabolism.