Luteinizing hormone releasing hormone (LH-RH) was been implicated in the mediation of sexual receptivity in the female rat. Prostaglandin E2 (PGE2) has been found to release LH-RH. The possibility that PGE2 [prostaglandin E2] might potentiate lordosis behavior in a similar way to LH-RH [luteinizing hormone-releasing hormone] was tested. All drug treatments increased L:M ratios [the ratio of the number of lordosis responses to the number of mounts, intromissions and ejaculations of the male] compared with estrone only levels, with progesterone being the most effective treatment, followed by PGE2 and LH-RH, which yielded similar L:M ratios, and then by PGE1. PGE2 significantly enhanced mating behavior over estrone-saline (P < 0001) and estrone-PGE1 (P < 001) levels. The quality of sexual receptivity produced by PGE2 was similar to that produced by LH-RH in that some hind-kicking and biting was observed in addition to the hopping, darting and soliciting behavior characteristic of a receptive female.