The endocrinology of extrapyramidal system disorders.

The study of endocrinologic changes in Parkinson's disease, Huntington's disease, and tardive dyskinesia may elucidate the pathophysiology of these disorders, especially the presence of hypothalamic lesions. There is probably a decrease in PRL concentrations in Parkinson's disease, and there may be an increase in TSH response to TRH stimulation. It is not clear if there is any change in GH concentrations in Parkinson's disease. There appears to be a robust increase in GH concentrations in Huntington's disease, and there may be a small increase in PRL as well. At present no endocrinologic abnormality has been well documented in tardive dyskinesia.