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Photic stimulation is required to elicit estrogen‐induced anorexia in rats
Author(s) -
Mabuchi Kaori,
Takano Azusa,
Hara Yayoi,
Morimoto Keiko,
Takamata Akira
Publication year - 2013
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.27.1_supplement.1123.7
Subject(s) - ovariectomized rat , endocrinology , medicine , stimulation , estrogen , photic stimulation , anorexia , food intake , body weight , weight gain , biology , neuroscience , visual perception , perception
Estrogen replacement in ovariectomized (OVX) rats reduces food intake specifically during the light phase. To test the hypothesis that enhanced response to photic stimulation during the light phase is involved in the mechanism for the anorexigenic and anti‐obesity effects of estrogen, we examined the effects of exposure to a constant dark environment (DD) and estrogen replacement on food intake and body weight change in OVX rats. Female Wistar rats were ovariectomized and implanted with either an estradiol (E2) or a cholesterol (Veh) capsule. Rats were then exposed to DD for 2 weeks. Other rats exposed to the12 h/12 h‐light/dark cycle condition (LD) served as control. Exposure to DD increased food intake during the subjective day but did not during the subjective night, and increased daily food intake in the E2 group. These changes occurred without phase shifting. DD exposure did not alter food intake either during the subjective day or night in the Veh group. Physical activity was increased by DD exposure during the subjective day in the both groups, and significantly decreased during the subjective night in the Veh group. Body weight gain under DD in the both groups was larger compared with that under LD. These data indicate that the anorexigenic effect of estrogen is dependent on the light environment, while photic stimulation attenuates body weight gain regardless of E2 replacement or physical activity.