5-HYDROXYTRYPTAMINE RECEPTOR FUNCTION IN HUMANS IS REDUCED BY ACUTE ADMINISTRATION OF HYDROCORTISONE

5-Hydroxytryptamine(1A) (5-HT1A) receptors have been shown to be suppr essed by corticosteroid hormones in a variety of animal experimental p aradigms. It has been suggested that this effect may be central to the pathophysiology of severe clinical depressive illness, a condition in which 5-HT1A receptor function is reduced and corticosteroid hormones are elevated. We report the effects of acute administration of hydroc ortisone in normal volunteers on a neuroendocrine model of 5-HT1A rece ptor function. Fifteen healthy male volunteers took part in a random o rder, double blind, placebo controlled study, in which 100 mg hydrocor tisone or placebo was administered 11 h before infusion of L-tryptopha n (L-TRP). Pre-treatment with hydrocortisone significantly reduced the growth hormone (GH), but not the prolactin (PRL) response to the infu sion. These data are consistent with the view that acute administratio n of corticosteroid hormones significantly impairs 5-HT1A receptor med iated function in healthy human volunteers and are in line with animal studies of the effects of corticosteroid hormones on 5-HT1A receptors . We propose that this finding is relevant to the pathophysiological p rocesses which cause severe depressive illness.