We report herein the effects of the beta-adrenergic agonist clenbuterol on desipramine (DMI)-induced growth hormone (GH), prolactin (PRL) and cortisol secretion in healthy male subjects. In the first study, nine subjects were treated with either clenbuterol (0.04 mg, p.o.) or placebo. In the second study, 12 subjects received either DMI (50 mg, i.v.) alone or in combination with clenbuterol (0.04 mg, p.o.) given 60 min prior to DMI administration. Clenbuterol alone had no influence on GH, PRL, or cortisol concentrations, compared to placebo. DMI alone caused GH stimulation (mean maximum = 15.7 +/- 3.4 ng/ml), which was significantly lower after combined administration of DMI and clenbuterol (mean maximum = 7.7 +/- 1.6 ng/ml) (p less than or equal to 0.01). DMI-induced PRL and cortisol stimulation was not influenced by clenbuterol pretreatment. These results indicate the inhibiting influence of noradrenergic beta-receptors on GH stimulation.