Nerve growth factor levels in Parkinson disease and experimental parkinsonian rats.

Nerve growth factor (NGF) is well established for its ability to promote growth and survival for specific neuronal populations. However, its participation in the pathogenesis of human nervous system disorders such as Parkinson's disease (PD) remains to be resolved. This study examined NGF levels in the serum of healthy persons, in patients with PD and in parkinsonian rats using a double site immune-enzymatic assay (EIA) with the murine 27/21 anti-beta-NGF monoclonal antibody. PD patients were divided in two groups according to the stages of the disease (Grade: I-II and Grade: III-IV of Hoenh and Yahr scale). NGF levels in parkinsonian rats showed significant (P<0.01) reductions when compared with serum from normal animals. The NGF levels in early states of the disease (Grade I-II) showed greater reductions (P<0.01) in comparison to those with advanced stages (Grade III-IV). We consider that alterations in NGF levels may reflect ongoing neurodegenerative processes in PD.