Progesterone Enhancement of Lysergic Acid Diethylamide and Levo-5-Hydroxytryptophan Stimulation of the Copulatory Response in the Female Rat
Neuroendocrinology March 26, 2008 Anni Sietnieks, Bengt J. Meyerson 11 citations
In female rats whose ovaries have been removed, sexual receptivity (the lordosis response) can be triggered by estrogen alone or estrogen plus progesterone. Large doses of LSD (≥50 μg/kg) or L-5-HTP (≥2.5 mg/kg) inhibit this behavior, with progesterone enhancing the inhibition. Conversely, small doses of LSD (5–30 μg/kg) increase lordosis when only estrogen is given. This study tested how different hormone treatments affect this stimulatory action. When lordosis was activated by estradiol benzoate alone, a 10 μg/kg dose of LSD increased the response within 10 minutes, but 1 μg/kg had no effect. However, when progesterone was also given, 1 μg/kg of LSD did increase lordosis. Similar results occurred with very small doses of L-5-HTP after certain pretreatments. Progesterone appears to influence serotonin-related mechanisms in this behavior.