Striatal deficiency of L-pyroglutamic acid in Huntington's disease is accompanied by increased plasma levels

L-Pyroglutamic acid (L-PGA), a cyclized glutamate analogue, was measured in plasma, cerebrospinal fluid and brain tissue of patients with Huntington's disease (HD) and controls. In HD, plasma L-PGA was elevated and possibly reflects an increased requirement of cell membranes to be protected against peroxidative damage. L-PGA was decreased in caudate and putamen of HD patients. We suggest that striatal deficiency of L-PGA in HD is a consequence of neuronal loss which characteristically occurs in HD striatum.