We have previously showed the expression of dopamine transporter (DAT), neutral amino acid transporter (LAT) and aromatic amino acid decarboxylase (AADC) in the striatal astrocytes, and that repeated L-DOPA treatment markedly induced expression of DAT and apparent DA-immunoreactivity in the reactive astrocytes in the striatum of parkinsonian animal models. It is thought that astrocytes can uptake both L-DOPA and DA via LAT and DAT, respectively. To clarify uptake, metabolism and release of L-DOPA in striatal astrocytes, the contents of L-DOPA, DA and their metabolites were measured after the L-DOPA treatment using cultured striatal astrocytes. The level of L-DOPA in astrocytes was markedly increased after 4-hr L-DOPA exposure, but DA was not detected. These results indicate that uptaken L-DOPA never be converted to DA in astrocytes, despite of expression of AADC. The level of uptaken L-DOPA in cultured striatal astrocytes was rapidly decreased after removing extracellular L-DOPA. Furthermore, apparent L-DOPA-immunopositive reactive astrocytes were increased in the striatum of L-DOPA-treated parkinsonian rats. Taken together, the present results suggest that striatal astrocytes act as a reservoir of L-DOPA to uptake or release L-DOPA depending on the extracellular L-DOPA concentration, but have less ability to convert L-DOPA to DA.