GNRH1 and neoplasm: To determine if GnRH and/or kisspeptin may potentiate or counter these effects of 5HT on tumor growth, COS were treated with doses (0.5, 3, 6, 12, and 25 μM) of this indoleamine for 24 h following treatment with either 1.0 nM GnRH or 10.0 nM kisspeptin, and proliferation was again evaluated via MTS assay.