Estrogens and antiestrogens: actions and interactions with fluphenazine on food intake and body weight in rats.

Treatment of ovariectomized rats for 3 days with 2 micrograms estradiol benzoate (E2B), 6 micrograms ethinyl estradiol, or 1-2 mg of either of the antiestrogens nafoxidine or tamoxifen led to similar decreases in food intake, body weight gain, adipose tissue lipoprotein lipase activity, and hepatic fatty acid synthetase activity, despite their different effects on uterine growth and induction of progestin receptors in pituitary and adipose tissue. Longer-term (2 wk) treatment with tamoxifen resulted in similar transient changes in food intake and body weight gain, as did treatment with E2B. Daily administration of 50 micrograms fluphenazine (FLU) led to significant decreases in body weight, although there was no change in food intake. Concurrent administration of FLU with either E2B or tamoxifen led to additive effects on body weight and food intake change. None of the treatments had any effect on in vitro binding of [3H]tamoxifen to antiestrogen binding sites in pooled hypothalamic-preoptic area samples.