Effects of stereoisomers of estradiol on food intake, body weight and hoarding behavior in female rats

The effects of 17-alpha and 17-beta estradiol on food intake, body weight and hoarding behavior in ovariectomised rats were investigated. For five days, ten animals received subcutaneous injections of both isomers (10 micrograms/kg/day) in a counterbalanced design. Hoarding tests were conducted on the last three days of each 5-day injection period. 17-Alpha estradiol significantly reduced food intake but was without effect on body weight. 17-Beta estradiol reduced food intake significantly more than the alpha form and also significantly reduced body weight. These differential effects suggest that stereoisomers of estradiol may be acting on separate regulatory systems. The treatments did not change hoarding activity compared to pre-treatment levels.