Serum insulin-like growth factor-1 and nitric oxide levels in Parkinson's disease.

The aim of this study was to investigate the role of circulating growth hormone (GH), insulin growth factor-1 (IGF-1), IGF binding protein-3 (IGFBP-3), and nitric oxide (NO) concentrations in the patients suffering from Parkinson's disease (PD). The study groups were consisted of 25 patients with PD and 25 matched healthy subjects as a control. The NO level of patients in PD group (2.3 +/- 0.4 micromol/L) was significantly lower than that in the control group (2.8 +/- 0.6 micromol/L) (P:.011). Although there were no statistically significant differences in the GH, IGF-1, and IGF BP-3 levels among the two groups, in this preliminary study, we found low NO and mildly elevated IGF-1 levels in the patients with PD. The results may be associated with adaptation or protective mechanisms in the neurodegenerative disease processes such as seen in the PD. Further studies should be carried out to confirm our results.