Food deprivation and the role of estradiol in mediating sexual behaviors in meadow voles

Abstract

Female mammals are particularly sensitive to changes in food availability. The mechanisms that affect sexual behavior and food intake are closely related to one another; chief among the mechanisms that control sexual behaviors in females is estradiol. In order to understand how food deprivation results in inhibition of sexual behavior (attractivity, proceptivity, and receptivity), we measured the effects of food deprivation on circulating concentrations of estradiol. We also determined whether estradiol treatment was sufficient to restore sexual behaviors in food-deprived female meadow voles. We found that estradiol titers of food-deprived female voles are significantly lower than those of ad lib-fed female voles. Further, we found that estradiol treatment was sufficient to restore proceptivity and receptivity in food-deprived, ovariectomized female voles. However, estradiol treatment was not able to overcome the food deprivation-induced inhibition of attractivity. Thus, decreases in estradiol titer of food-deprived female voles may be related to the suppression of their proceptive and receptive behaviors, and may be a mechanism that allows females to avoid mating when conditions are not propitious for their survival and that of their offspring.

Figure 1

Mean ± SEM of estradiol titers of female voles in after being food deprived for different intervals. Also shown are the mean estradiol titers for the ad lib-fed and food deprived OVX-E₂ treated female voles. There were no statistical differences between the groups of females.

Figure 2

Mean ± SEM time (s) male voles spent investigating odors of OVX+E₂, ad lib-fed vs. odors of OVX + blank, ad lib-fed female voles. Significant difference designated by ** indicates P < 0.01.

Figure 3

The mean ± SEM time (s) male voles spent investigating odors of (A) OVX+E₂, ad lib-fed females compared to those of OVX+E₂, FD 12 h females and the odors of (B) OVX+E₂, 12 h food-deprived females compared to those of OVX + blank, ad lib-fed females. Significance differences signified by * indicates P <0.05, and ** indicates P < 0.01.

Figure 4

The mean time (s) ± SEM time (s) male voles spent investigating odors of (A) OVX+ E₂, 24 h food-deprived compared to those of OVX+ E₂, ad lib-fed females and odors of (B) OVX+ E₂, 24 h food-deprived females compared to those of OVX + blank, ad lib-fed females. Significance differences signified by * indicates P <0.05, and ** indicates P < 0.01.

Figure 5

The proportion (mean ± SEM) of time (S) female voles spent investigating the odors of male conspecifics. Different letters designate significant differences at P < 0.05.

Figure 6

The proportion of female voles from the different treatment groups that displayed receptivity when paired with sexually experienced male voles. Different letters designate significant differences at P < 0.05.