Effect of fluoxetine on noradrenergic mediated growth hormone release: a double blind, placebo-controlled study

Twelve patients with DSM-III-R major depressive illness were tested for growth hormone (GH) response to desipramine (DMI), a noradrenergic (NA) reuptake inhibitor. The response is mediated by NA alpha 2 receptors. They were then randomly assigned to treatment under double-blind conditions with either fluoxetine, the highly selective serotonin reuptake inhibitor or placebo. After 4 weeks they were retested. Fluoxetine but not placebo was effective in promoting recovery in four of the six patients treated. Patients treated with fluoxetine showed a significant decrease in DMI-mediated GH release irrespective of therapeutic outcome. This is consistent with marked alteration of NA function and raises questions as to the selectivity of fluoxetine.