Neuroendocrine responses to apomorphine in depressed patients and healthy control subjects.

Increasing evidence implicates altered dopamine function in major affective illness. In the present study, growth hormone responses to the dopamine agonist apomorphine were not different for 14 male depressed patients and 16 healthy male volunteers. Baseline and post-apomorphine prolactin levels were lower for the depressed patients than the control subjects, but the percent decrease following apomorphine was not different for the two groups. Neuroendocrine responses were not significantly altered during chronic treatment with the dopamine agonist piribedil. These neuroendocrine results suggest that decreased baseline prolactin levels in depressed patients do not reflect altered postsynaptic receptor sensitivity in the tuberoinfundibular dopamine system.