Acute endocrine correlates of attack by lactating females in male mice: effects on plasma prolactin, luteinizing hormone and corticosterone levels.

Immediately following defeat inflicted by lactating Rockland-Swiss (R-S) albino mice, adult R-S male mice exhibited significant reductions in circulating prolactin (PRL) and luteinizing hormone (LH), but not corticosterone (CORT). These results suggest that acute neuroendocrine responses to intersex competition may be as dramatic as those previously reported for intermale encounters.