Facilitation of lordosis behavior in the ovariectomized estrogen primed rat by dibutyryl cAMP

The effect of systemic administration of various dosages of db cAMP (0.5, 1, 2, 8 and 16 mg) on the sexual behavior of ovariectomized estrogen primed rats (2 μg of EB administered 44 hours before dibutyryl cAMP) was studied. All but the low dose of db cAMP elicited lordosis in at least 50% of the rats. The response to db cAMP varied greatly among subjects. No dose response relationship was observed within the dose range of db cAMP employed. Theophylline (10 mg) administered simultaneously to db cAMP increased and prolonged the action of the nucleotide. Bilateral infusion of 50 μg of db cAMP into the medial preoptic area of estrogen primed rats elicited lordosis behavior in four out of eight animals. Dibutyryl cAMP did not produce sequential inhibition. The results suggest that a rise in the intracellular level of cAMP is involved in the hormone facilitation of sexual behavior in estrogen primed rats.