BACKGROUND: Serotonin (5-HT) agonists are reported to affect prolactin (PRL) and gonadotropin secretion. A small study was conducted on male patients with generalized anxiety disorders to investigate the clinical and neuroendocrinological effects of the 5-HT(1A) receptor agonist tandospirone (TDS) on the hypothalamo-pituitary-gonadal (HPG) axis.
METHODS: The subjects for the present study included 11 male outpatients. Informed consent was obtained from all subjects involved in this study. The endocrine studies were done before and during TDS administration. Psychiatric ratings were done using the Japanese version of the Spielberger's State-Trait Anxiety Inventory.
RESULTS: We found that both state- and trait-anxiety scores were significantly reduced by TDS treatment; there was no significant difference in PRL, gonadotropins or testosterone (T) between the patients and normal controls; TDS administration showed significant stimulatory effects on PRL and T; and PRL change between baseline and TDS steady state (DeltaPRL) did not show a significant correlation with improvement in state or trait-anxiety scores.
CONCLUSIONS: Our results indicate that PRL response may not provide a clinical predictor; (2) PRL level may not reflect the level of anxiety, and 5-HT(1A) may have stimulatory effects on PRL. However, further, double-blind evaluation with a larger sample would be needed for clarification of effects of 5-HT(1A) on the HPG axis.