AJP - Regulatory, Integrative and Comparative Physiology, Vol 264, Issue 6 1219-R1223, Copyright © 1993 by American Physiological Society
Tamoxifen mimics the effects of estradiol on food intake, body weight, and body composition in rats
G. N. Wade and H. W. Heller
Department of Psychology, University of Massachusetts, Amherst 01003.
Treatment of ovariectomized rats with the nonsteroidal antiestrogen
tamoxifen mimicked the effects of estradiol and caused significant
decreases in food intake and body weight. The decreases in body weight were
reflected mainly in a decreased body fat content, although tamoxifen
treatment did suppress linear growth too. Similar to the effects of
estradiol, tamoxifen decreased parametrial white adipose tissue wet weight
and lipoprotein lipase activity. When given concurrently with estradiol,
tamoxifen showed no evidence of antiestrogenic activity on any of these
measures. As reported previously, tamoxifen acted as a partial
agonist/antagonist for uterine weight. The effective dose of tamoxifen for
suppression of food intake, body weight, and body fat content fell between
10 and 50 micrograms/day. Therefore, tamoxifen behaves like other
nonsteroidal antiestrogens and mimics but fails to antagonize the actions
of estradiol on many aspects of physiological and behavioral regulation of
energy balance.
