The neuroendocrine effects of the 5-HT receptor agonist, sumatriptan (
6 mg subcutaneously), were studied in 11 healthy male subjects using a
placebo-controlled, cross-over design. Compared to placebo, sumatript
an significantly lowered levels of plasma prolactin but increased thos
e of plasma growth hormone. There was no effect on plasma cortisol con
centrations. The neuroendocrine effects of sumatriptan differ from tho
se of previously described 5-HT-receptor agonists, and may be a conseq
uence of selective activation of 5-HT1D or 5-HT1B receptors. However,
the present data cannot exclude the possibility that the neuroendocrin
e changes reflect nonspecific stress responses or changes in pituitary
blood flow.