Hypothalamic-pituitary-gonadal axis in major depressive disorders

Area of Science:

• Neuroendocrinology
• Psychiatry
• Reproductive Endocrinology

Background:

• Major depressive disorder (MDD) is associated with neuroendocrine dysregulation.
• The hypothalamic-pituitary-gonadal (HPG) axis and hypothalamic-pituitary-adrenal (HPA) axis may interact in the pathophysiology of depression.

Purpose of the Study:

• To investigate baseline and stimulated luteinizing hormone (LH), follicle-stimulating hormone (FSH), and testosterone levels in patients with acute major depressive disorder.
• To compare hormonal profiles between depressed patients and healthy controls, and between acute depression and remission states.
• To explore the relationship between HPA axis activation (via DST) and HPG axis function in depression.

Main Methods:

• Assessed baseline LH, FSH, and testosterone levels in 28 patients with acute MDD and 20 healthy controls.
• Administered TRH-LHRH to measure LH and FSH response (delta LH, delta FSH).
• Reinvestigated 22 patients in remission and performed cross-sectional and longitudinal comparisons, stratified by sex and menopausal status.

Main Results:

• Depressed males with abnormal dexamethasone suppression test (DST) response exhibited significantly higher delta FSH during acute depression compared to controls (P < 0.03).
• Longitudinally, these males showed decreased testosterone levels and increased delta FSH in the acute state versus remission.
• No correlation was found between HPG axis hormones and melatonin, prolactin (PRL), or thyrotropin-releasing hormone (TRH)/LHRH-stimulated thyroid-stimulating hormone (TSH) response.

Conclusions:

• The results do not support a hypothesis of stimulus-induced downregulation of pituitary LHRH receptors in depressed patients.
• The mechanisms linking HPA axis activation to HPG axis alterations in depression require further investigation.