Growth hormone and prolactin secretion in Huntington's disease.

Growth hormone (GH) and prolactin (PRL) secretion was studied in twelve patients with Huntington's Disease, eight unaffected relatives, and twenty normal subjects in response to provocative and suppressive tests. Prolactin responses to TRH, chlorpromazine, L-DOPA, and apormorphine were similar in all groups with the exception of a slightly blunted PRL response to THR in the unaffected relatives. Although GH responses to L-DOPA were similar in all groups, patients with Hungtinton's Disease had nearly absent GH responses to apomorphine (mean peak GH = 1.4±0.4 (SE) ng/m1) compared to normal control subjects (mean peak GH = 28.9±8.6 ng/m1). These results, which are similar to some previously reported findings in drug-induced tardive dyskinesia, suggest an abnormality in dopamine-mediated GH secretion in Huntington's Disease.