GONADOTROPIN (LH AND FSH) RESPONSE AFTER SUBMAXIMAL GNRH STIMULATION IN DEPRESSED PREMENOPAUSAL WOMEN AND HEALTHY CONTROLS

Although hormonal response abnormalities in depression have been demonstrated in several hypothalamic-pituitary-target organ axes after a variety of neuroendocrine challenge tests, studies of hypothalamic-pituitary-gonadal (HPG) axis function have been inconsistent in their findings. The use of maximal or supramaximal doses of gonadotropin-releasing hormone (GnRH) in early studies (150-600 mu g) may have masked the presence of more subtle disturbances in luteinizing hormone (LH) and follicle-stimulating hormone (FSH) responsiveness in depression. We hypothesized that submaximal doses of GnRH might reveal a more subtle dysregulation in gonadotropin responsiveness in depression, and therefore measured LH and FSH responses after GnRH 10 mu g and 90 mu g doses in nine premenopausal depressed women and six healthy controls. There were no statistically significant differences between subject groups for mean basal LH, FSH, and estradiol concentrations, nor for any of the LH and FSH response values after either GnRH stimulation dose. The present observations of an intact HPG axis in depression contrast with findings of disturbances in most other hypothalamic-pituitary axes, and suggest that neuroendocrine dysregulation in depression might not represent a generalized limbic system-hypothalamic-pituitary abnormality, but rather a more restricted lesion sparing the medial preoptic and/or arcuate region of the hypothalamus which regulates gonadotropin secretion.