(OXY) produces a significant increase in maternal behavior in ovariectomized (OVXed) rats
given a single priming dose of estrogen. Arginine vasopressin (AVP) has a weaker and
more delayed but significant facilitating effect on the onset of maternal behavior. Other
investigators have demonstrated that prolonged treatment of OVXed nulliparous rats with
estrogen and progesterone followed by withdrawal of progesterone shortens the latency of …