Effect of L-dopa on plasma free fatty acids and plasma glucose

Abstract

The effect of L-dopa, the levoisomer of dihydroxyphenylalanine and a precursor of catecholamines, on plasma free fatty acids (FFA) and plasma glucose was studied in dogs and in patients with Parkinson's disease. L-dopa increased plasma FFA and plasma glucose in both dog and man. L-dopa administered intravenously to dogs caused prompt and significant rise in plasma FFA and sugar, while oral dosing produced only slight changes that were first seen 90 min after administration. Variation in the mode of administration of L-dopa, shown in a previous study to affect its absorption, caused differences in the rate and magnitude of increase in plasma FFA and glucose. Parkinsonian patients who had prompt and high serum peak levels of L-dopa showed a significant increase in the plasma FFA and glucose, persisting for 6 hr. Patients with the low serum levels of L-dopa did not show a significant increase in plasma FFA or glucose.