Noradrenergic receptor sensitivity in obsessive-compulsive disorders: I. Growth hormone response to clonidine stimulation.

In 15 patients with obsessive-compulsive disorder (OCD) and in 15 healthy controls postsynaptic alpha-2-adrenoceptor sensitivity was examined by measuring the growth hormone (GH) response to growth hormone-releasing hormone (GHRH) and to clonidine stimulation. Basal values of GH and somatomedin-C (SMD-C) and mean GH responses to GHRH were the same in patients and controls, thus suggesting that a peripheral pathology of the somatotropic axis should not be present. GH responses to clonidine stimulation were blunted in patients suggesting that post-synaptic alpha-2-adrenoceptors are subsensitive, possibly due to higher than normal noradrenergic secretion.