Elicitation of male mouse (Mus musculus) ultrasonic vocalizations: I. Urinary cues.

Abstract

Experiments (18) examined the physical characteristics and physiological modulation of the ultrasound-eliciting property of female urine. An excitatory factor probably exists in female urine. Male urine is essentially neutral with regard to ultrasound elicitation. The ultrasound-eliciting factor is relatively nonvolatile and heat resistant, although extreme heat will destroy its activity. A minor modulating effect of ovarian hormones upon ultrasound-eliciting potency was suggested. Ovarian hormones accounted for only a small proportion of the variability between females and males. Adrenal hormones also appeared relatively unimportant. Exogenous androgen suppresses female urinary ultrasound-eliciting activity, but this effect may not be directly relevant to normal male-female differences in urinary potency. Castration of males in adulthood or on the day of birth did not improve the ability of their adult urine to elicit ultrasounds. Administration of androgen to neonatal females did not suppress the ability of their adult urine to elicit ultrasounds. Hypophysectomy eliminates the ultrasound-eliciting properties of female urine, which suggests that the dimorphism in ultrasound elicitation may be regulated by pituitary hormones.