Abstract

The experiments presented in this thesis investigated the combined effects of lactation and food restriction in rats. The ability of exogenous estrogen administration to stimulate both receptive and proceptive behaviours were examined in addition to both active and passive rejection responses. In experiment 3, the effect of testing situation was studied. Females in this experiment, unlike either Experiment 1 or 2, were allowed to pace their copulatory contacts with the male. The results of these experiments demonstrate that lactating females are able to respond to the stimulatory effects of exogenous estrogen administration on the induction of the lordosis reflex. Interestingly though, females tested, on Day 15 postpartum responded with much lower lordosis quotients compared to ovariectomized controls. Overall, unlike receptive behavior, proceptive behaviors were observed to increase across days postpartum. Finally, in Experiment 3, females that were allowed to pace their contacts with the male, showed no differences in passive rejection responses, receptivity or proceptivity. Active rejection responses followed a different pattern in Experiment 3 from that obtained in Experiment 2.