Fifteen patients with Parkinson's disease underwent open transplantation of autologous adrenal medulla to the caudate nucleus. Motor function was evaluated before and after surgery and was found to be significantly improved at 5-9 months following surgery. Cerebrospinal fluid was taken from the ventricle adjacent to the implant site at the beginning of the operation and at 1 week, 3 months, and 5-9 months following surgery. The cerebrospinal fluid was assayed for chromogranin A (CgA), the major soluble protein in chromaffin granules, and basic fibroblast growth factor (bFGF), a neurotrophic growth factor found in normal brain and adrenal medulla. CgA levels did not increase following surgery, suggesting that a significant number of chromaffin cells did not survive or that surviving chromaffin cells did not secrete a significant amount of CgA. Basic fibroblast growth factor was undetectable in the ventricular cerebrospinal fluid. © 1991.