Blunting of noradrenergic-stimulated growth hormone release in mania

Seven drug-free patients with bipolar affective disorder, currently in a manic phase, underwent desipramine-induced growth hormone (GH) stimulation, as did seven healthy age- and sex-matched subjects. There was significant blunting of GH release in the manic patients, suggesting a down-regulation of alpha 2-noradrenergic responses. Blunting of GH release was not related to severity of symptoms, duration of illness, or age. Similar blunting has previously been described in depressed patients.