Cortisol, ACTH, prolactin and beta-endorphin responses to fenfluramine administration in major-depressed patients

In the past, some researchers found increased cortisol and prolactin responses to the administration of fenfluramine in major-depressed patients. It was believed that the fenfluramine test could prove to constitute another challenge probe to reflect the central serotonergic function. The present study was conducted in order to investigate the pituitary/adrenal responses to fenfluramine in major- versus minor-depressed patients. To this end we administered 60 mg D,L-fenfluramine p.o. to 40 depressed patients categorized according to the DSM-III. The basal levels of cortisol, adrenocorticotrophic hormone (ACTH), beta-endorphins and prolactin and their levels 2 and 4 h after fenfluramine administration were measured. We found no significant effect for fenfluramine treatment on cortisol, ACTH or beta-endorphins. There was a significant (p = 0.02) effect for fenfluramine treatment on prolactin. The enhanced secretion of prolactin was only significant (p = 0.006) in major (296.X2, 296.X3, 296.X4) and not in minor (300.40, 309.00) depressives. It was concluded that our findings corroborate the thesis of a hypersensitive serotonergic neurotransmission during a major depressive episode.