Postovariectomy weight gain in female rats is reversed by estrogen receptor α agonist, propylpyrazoletriol

OBJECTIVE: The objective of this study was to distinguish the role of specific estrogen receptors (ERs), ER alpha and ER beta, on body weight regulation using a rat model of weight gain subsequent to menopause. STUDY DESIGN: Ovariectomized rats were utilized as the animal model to simulate the postmenopause weight gain. The rats were ovariectomized and subcutaneously injected daily with vehicle, estradiol-17 beta (E2), propylpyrazoletriol (PPT; ER alpha agonist) and diarylpropionitrile (DPN; ER beta agonist). To further control for the possible effect of estrogen secreted from adrenals, a second experiment was conducted during which the rats were adrenalectomized and ovariectomized. RESULTS: Ovariectomy significantly increased (P < .05) body weight, whereas treatment of ovariectomized rats with E2 and PPT, but DPN decreased (P < .05) body weight. The results from the second study with ovariectomized/adrenalectomized rats were consistent with the first experiment. CONCLUSION: These results suggest that the activation of ER alpha is important in regulating body weight.