L‐Tryptophan and prolactin release: Evidence for interaction between 5‐HT₁ and 5‐HT₂ receptors

Abstract

Abstract The effects of the selective 5‐HT 2 receptor antagonist, ritanserin, on the growth hormone (GH) and prolactin (PRL) responses to intravenous L‐tryptophan (LTP) were assessed in 8 normal volunteers. Administration of ritanserin (40 mg orally) prior to infusion of LTP (5 g) significantly enhanced the PRL responses but not those of GH. The results are consistent with previous proposals that the endocrine responses to LTP are mediated by 5‐HT 1 rather than 5‐HT 2 receptors and also suggest that 5‐HT 2 receptor antagonists may increase certain 5‐HT 1 mediated responses in the human brain.