Sex differences in sensitivity of food intake, body weight, and running-wheel activity to ovarian steroids in rats.

The effects of sex and experimental androgenization on the responsiveness of food intake and running-wheel activity to exogenously administered ovarian hormones were investigated in adult, gonadectomized rats. Food intake was found to be analogous to lordotic behavior in that males and neonatally androgenized females were relatively insensitive to the influences of either estradiol benzoate (EB) or progesterone (P). Running-wheel activity, however, could be differentiated from food intake in that males responded the same as females to the effects of EB and P. Androgenized females (500-mug testosterone propionate on the third day of life) showed a response to EB quantitatively equivalent to that of nonandrogenized females, but they had a longer latency to respond. The estrogen-antagonistic effects of P were confirmed for both of these behaviors, and there was a positive correlation between the magnitude of the responses to EB and P.