Reserpine: inhibition of olfactory blockage of pregnancy in mice.

Failure of pregnancy in newly mated female mice exposed to fresh urine from alien males is prevented by administration of reserpine, at 6.25 micrograms per day per female, on days 1 to 5 post coitum-that is, throughout the period of exposure to male urine and for 2 more days. Since reserpine is known to suppress the inhibitory center in the hypothalamus controlling the release of prolactin, inhibition by reserpine of the blockage of pregnancy provides a strong direct indication of hypothalamic mediation in the male-induced failure of pregnancy in mice.