To test the hypothesis that hypothalamic β-endorphin levels were related to the body weight changes occurring with ovarian steroid treatments, 80 adult female Sprague-Dawley rats were ovariectomized and allowed to recover for 7 days. Four treatment groups of 20 each were subjected to daily injections for 14 days with A) oil, B) β-estradiol benzoate (2µg), C) β-estradiol benzoate (2µg) plus progesterone (5mg), or D) progesterone (5mg). Weight gain was significantly (p < 0.01) lower in the estrogen group when compared to the control, estrogen/progesterone, or progesterone groups. The estrogen/progesterone-treated group gained significantly less weight than either the control or progesterone group. A significant (p < 0.05) decrease in food intake was also observed in the estrogen and estrogen/progesterone groups when compared to the control and progesterone groups, but not between each other. The progesterone-treated group was not significantly different from the controls in either weight gain or food intake. Hypothalamic β-endorphin (ng/mg protein) concentrations were significantly (p < 0.05) higher in the estrogen- and estrogen/progesterone-treated groups compared to the control and progesterone groups. Again, much like the weight gain, food intake, and hypothalamic β-endorphin (ng/mg protein), the estrogen and estrogen/progesterone groups had significantly (p < 0.05) heavier adrenal weights when compared to the controls and progesterone groups. There was no significant difference in plasma corticosterone levels between any of the groups. In this study, hypothalamic β-endorphin (ng/mg protein) appeared to be effected by ovarian steroid hormone treatment. Whether this is related to the weight gain also observed with the treatments remains to be determined. / Ph. D.

Thesis (Ph.D.)--University of Alberta, 2009. / A thesis submitted to the Faculty of Graduate Studies and Research in partial fulfillment of the requirements for the degree of Doctor of Philosophy, Food Science and Technology, Department of Agricultural, Food, and Nutritional Science. Title from pdf file main screen (viewed on January 10, 2010). Includes bibliographical references.

Diss. (sammanfattning) Stockholm : Karolinska institutet, 2005. / Härtill 5 uppsatser.