Comparison of growth hormone response after clonidine and insulin hypoglycemia in affective illness.

Abnormal growth hormone (GH) responses have been observed after several neuroendocrine challenge tests. In the present study, we examined the relationship between GH response after clonidine and insulin administration within the same subject to see if consistent response patterns were evident. Though there was a significant reduction in the mean GH response after clonidine (p = 0.0002), similar differences were not observed after insulin (p = 0.10). Furthermore, there were no apparent within-subject correlations for GH response between the clonidine and insulin challenge tests. Although the present findings indicate an inherent variability in GH response patterns after different neuroendocrine challenge tests, it appears from prior studies that GH may be more consistently blunted after clonidine in depression when compared to other GH provocative tests.