The quality of hormonally stimulated maternal behavior in ovariectomized rats

Maternal behavior was induced in ovariectomized female rats through injections of estradiol, progesterone, and prolactin followed by continuous pup exposure. This behavior was compared with that of pup-exposed, vehicle-injected, ovariectomized females and of parturient females on a wide variety of measures. The hormone injections did not significantly reduce retrieval latency. However, the performance of hormone-injected females on other measures, especially measures of pup-directed behaviors and of nest building, was markedly superior to that of ovariectomized females and similar to that of parturient animals. These results suggest that the hormonal factors which normally facilitate rapid onset of maternal behavior may not be identical to those affecting the quality of the behavior displayed.