Hydroxyl radical and superoxide dismutase in blood of patients with Parkinson's disease: relationship to clinical data.

Hydroxyl radical (.OH) levels in blood, superoxide dismutase (SOD) activity in plasma (plasma-SOD) and in red blood cells (RBC) relative to Cu,Zn-SOD (SOD1) protein (RBC-SOD/SOD1), SOD1 protein in RBC (SOD1/RBC) and plasma (SOD1/plasma), and Mn-SOD protein in plasma (SOD2/plasma) were measured in patients with Parkinson's disease (PD), multiple-system atrophy (MSA) with parkinsonism, and in control subjects. Patients with PD had significantly higher.OH and plasma-SOD values and significantly lower RBC-SOD/SOD1 and SOD1/RBC values than the corresponding MSA and control values. In PD, RBC-SOD/SOD1 values were significantly lower in older patients and were negatively correlated with age.OH levels were significantly higher in PD patients with early onset, a long period of illness or severe Yahr stage, and were negatively correlated with onset and positively correlated with duration of illness. RBC-SOD/SOD1 values in PD patients who received pergolide therapy were significantly higher than those in PD patients who received neither pergolide nor bromocriptine therapy. Therefore, the higher.OH level and the lower SOD1 activity may play a role in the onset and progression of PD, and pergolide may act neuroprotectively by inducing SOD1 activity.