Meeting Abstract

P2.23  Wednesday, Jan. 5  Behavioral effects of phytoestrogens in male and female rats TORREGROSSA, A-M.*; ECKEL, L.A.; Florida State University, Tallahassee; Florida State University, Tallahassee torregrossa@neuro.fsu.edu

There are a large number of plant secondary compounds in the human diet and in the last 30 years there has been increased interest in the estrogenic activity of soy. The effects of endogenous estrogens on activity, food intake and body weight are well studied so we chose to examine the effects of phytoestrogens on the food intake of developing animals. We raised rats on diets laced with genistein (190 ppm) and daidzein (150 ppm), the largest class of phytoestrogens found in soy products. Males and females were bred and maintained on this diet as well as a nutritionally identical diet with no phytoestrogens. A group of littermates were switched from the diet they were bred on to the opposite diet at puberty. Lastly, a third group of littermates was maintained on their maternal diet but were given access to a running wheel from weaning through adulthood. Daily body weight, food intake, running wheel activity (when available) and estrous stage were recorded for 65 days after weaning. There was no effect of maternal diet on weight at weaning, activity or puberty onset. In adulthood, females raised on the phytoestrogen diet were on average 8% smaller and ate an average of 12% less than females raised on the diet without phytoestrogens in both the sedentary and active conditions. However, the diets had no measurable effect on the intake or body weight of the males throughout life. Similar results occurred in the animals who switched diets at puberty. Together these data suggest be an interaction between the dietary phytoestrogens and the endogenous estrogen produced after puberty in female rats. Supported by NIH 5 T32 DC000044 & DK73936