ASYMMETRY IN PROGESTIN RECEPTOR LEVELS AND SEXUAL-BEHAVIOR IN FEMALE RATS

There are reports of hemispheric asymmetry in the control of sexual re ceptivity by the hypothalamus in the female rat. In the present study, we investigated whether there is an asymmetry in the distribution of progestin receptors in the hypothalamus, and whether the asymmetry in distribution is associated with receptivity as indicated by lordosis q uotients. Degree of hemispheric asymmetry in hypothalamic progestin re ceptor (PR) levels was associated with higher lordosis quotients regar dless of the direction of asymmetry. In a second study, as in the firs t study, degree (and not direction) of asymmetry of PR levels in the h ypothalamus was associated with receptive behavior. Ln addition, the r esults suggest a possible link between left-biased asymmetry in fronta l cortical PR levels and preceptive behavior. These studies are the fi rst evidence of relationships between hemispheric asymmetry in progest in receptor levels and behavior.