Low cerebrospinal fluid somatostatin in Parkinson disease: an irreversible abnormality.

In 39 parkinsonian patients, CSF somatostatin content was 88.0 +/- 4.1 pg per milliliter, which was about 40% less than in controls (147.3 +/- 5.1 pg per milliliter). Somatostatin values were unrelated to age, sex, body weight, total CSF protein, immunoglobulin, or cell count in either group. Parkinsonian values were not related to duration of disease, severity, specific signs, or treatment. In contrast to multiple sclerosis, in which CSF somatostatin is low only during relapses, the low somatostatin content of CSF in Parkinson disease seems to be irreversible, to be present at the onset of symptoms, and to imply an irreparable functional or structural alteration of somatostatin-secreting neurons.