The present study was conducted to investigate whether a single oral dosage of 20 mg of the selective serotonin reuptake inhibitor citalopram could be used as a tool to stimulate hormone secretion in neuroendocrine challenge paradigms. A total number of 48 healthy male subjects received either 20 mg citalopram or placebo in a randomized, double-blind cross-over design at an interval of 1 wk between both sessions. Citalopram was well tolerated without side-effects. Growth hormone (GH), prolactin (Prl) and cortisol (Cort) were determined in blood samples obtained at different time-points across the experiment according to drug kinetics. While GH and Prl were not changed after citalopram Cort levels increased as compared to the placebo condition, significantly about 2 h after drug intake. Results will be discussed in respect of the question of whether or not Prl and GH responses after treatment with i.v. applications of SSRIs reflect sertonergic involvement.