Ovarian hormones inhibit fat intake under binge-type conditions in ovariectomized rats

Zhiping Yu, Nori Geary, Rebecca L. Corwin

Research output: Contribution to journalArticle

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Abstract

Binge eating is more common in females than in males. This study investigated the effects of ovarian hormones on binge-eating behavior in a diet-related rat model. Six groups of ovariectomized Sprague-Dawley rats were used (n = 13/group). All rats had continuous access to chow and water throughout the study. One half of the rats were injected every fourth day with estradiol benzoate (2 μg/100 μl sesame oil) and progesterone (500 μg/100 μl sesame oil); the other half received only the sesame oil vehicle. Three feeding protocols were tested in each hormone injection condition: (1) chow only: no additional dietary fat access; (2) low-restriction: 1-h fat access every day; (3) high-restriction: 1-h fat access on Monday, Wednesday, and Friday. As previously reported in intact male and female rats, the high-restriction groups exhibited binge-like increases in 1-h energy intake during fat access. The major new finding of this study is that 1-h energy intake was tonically, but not cyclically, reduced in the hormone-treated high-restriction (binge) rats. Specifically, both low- and high-restriction hormone-treated rats consumed significantly less energy than did the oil-treated rats during the 1-h fat period (p < 0.0001) and overall (p < 0.0001), indicating a tonic inhibition of eating. However, food intake during the 1-h fat access period was also cyclically reduced in the hormone-treated low-restriction rats, but not in the hormone-treated high-restriction rats. These results indicate that the normal cyclic inhibitory influence of ovarian hormones on eating, but not their normal tonic inhibitory influence, is disrupted by conditions leading to binge-type eating.

Original languageEnglish (US)
Pages (from-to)501-507
Number of pages7
JournalPhysiology and Behavior
Volume95
Issue number3
DOIs
StatePublished - Oct 20 2008

Fingerprint

Fats
Hormones
Sesame Oil
Bulimia
Eating
Energy Intake
Dietary Fats
Feeding Behavior
Progesterone
Sprague Dawley Rats
Oils
Diet
Injections
Water

All Science Journal Classification (ASJC) codes

  • Experimental and Cognitive Psychology
  • Behavioral Neuroscience

Cite this

Yu, Zhiping ; Geary, Nori ; Corwin, Rebecca L. / Ovarian hormones inhibit fat intake under binge-type conditions in ovariectomized rats. In: Physiology and Behavior. 2008 ; Vol. 95, No. 3. pp. 501-507.
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Ovarian hormones inhibit fat intake under binge-type conditions in ovariectomized rats. / Yu, Zhiping; Geary, Nori; Corwin, Rebecca L.

In: Physiology and Behavior, Vol. 95, No. 3, 20.10.2008, p. 501-507.

Research output: Contribution to journalArticle

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