DOPAMINE FUNCTION IN OBSESSIVE-COMPULSIVE DISORDER - GROWTH-HORMONE RESPONSE TO APOMORPHINE STIMULATION

Indirect observations suggest that the dopaminergic system may be invo lved in the pathophysiology of obsessive-compulsive disorder (OCD). Th e dopaminergic function of 15 patients with OCD and 15 age/sex-matched controls was evaluated by measuring the growth hormone (GH) responses to stimulation with the dopaminergic agonist apomorphine (APO), which increases growth hormone-releasing hormone (GHRH), GH, and somatomedi ne C (SMD-C) secretions, Therefore, we measured basal plasma GH and SM D-C concentrations and GH responses to GHRH stimulation to exclude tha t a downstream pathology of the somatotropic axis could obscure the si gnificance of the results of the APO rest. The response of prolactin ( PRL) to APO inhibition were also measured. Basal plasma levels of GH, SMD-C, and PRL, GH responses to GHRH stimulation and PRL responses to APO inhibition did not differ in the two groups of subjects. GH respon ses to APO stimulation were blunted in obsessive-compulsive (OC) patie nts. The emetic response to the same stimulation was stronger in patie nts than in controls. These responses suggest that in our OC patients there is a dysregulation of the dopaminergic system, which is possibly expressed in different ways in the various areas of the central nervo us system. (C) 1997 Society of Biological Psychiatry.