Secretion of Luteinizing Hormone in Male Mice: Factors that Influence Release during Sexual Encounters*

Abstract

These experiments represent a search for factors that influence the secretion of LH in male mice during sexual encounters. Sequential changes in blood levels of LH were monitored in cannulated tethered males during their exposure to estrous females, ovariectomized females, urine pooled from all stages of the estrous cycle, or appropriate control conditions. Males that experienced spontaneous episodic LH release immediately before external stimulation did not secrete LH in response to any of the female stimulus conditions. Otherwise, the initial reaction to estrous females, ovariectomized females, and urine was an identical acute release of LH that typically returned to baseline in 45 min. Males that ejaculated 25 min or more after their initial LH response also experienced a second surge of hormone release, but males ejaculating before that time did not surge twice. A second exposure to urine 50 min after the first exposure yielded no LH response. These results suggest that the pattern of LH secretion in ...