2 PC12 PHEOCHROMOCYTOMA LINES SEALED IN HOLLOW FIBER-BASED CAPSULES TONICALLY RELEASE L-DOPA INVITRO

Two PC12 cell-derived lines have been studied following encapsulation into polymer-based hollow fibers with respect to secreted catecholamin es and their metabolites. Cellular encapsulation provides a chronic mi croperfusion environment within which basally secreted PC12 products c an be readily measured. Encapsulated PC12 cells grown and held under t he conditions specified in this report basally release amounts exceedi ng their total cellular stores of the dopamine precursor L-DOPA and th e electrochemically active dopamine metabolites DOPAC and HVA during 4 5-min static incubations. Under these same conditions, these cells rel ease less than 0.1% of their total cellular store of dopamine. Depolar izing incubations enhance dopamine secretion eightyfold and enhance se cretion Of L-DOPA, HVA, and DOPAC about twofold. The relative composit ion of products basally secreted differs between PC12-derived cell lin es, and an inverse relationship exists between basal release of L-DOPA and total cellular store of dopamine. These results further indicate that selected PC12 cell lines are potentially a source of both dopamin e and L-DOPA in therapeutic cellular replacement applications.