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The estrous cycle regulates rhythms of locomotor activity, body temperature, and circadian gene expression. In female mice, activity increases on the night of proestrus, when elevated estrogens cause ovulation. Exogenous estradiol regulates eating behavior rhythms in female mice fed a high-fat diet, but it is unknown whether endogenous estrogens regulate eating rhythms. In this study, we investigated whether diurnal and circadian eating behavior rhythms change systematically across the estrous cycle. We first studied diurnal eating behavior rhythms in female C57BL/6J mice in 12L:12D. Estrous cycle stages were determined by vaginal cytology while eating behavior and wheel revolutions were continuously measured. The mice had regular 4- to 5-day estrous cycles. Consistent with prior studies, the greatest number of wheel revolutions occurred on the night of proestrus into estrus when systemic levels of estrogens peak. The amplitude, or robustness, of the eating behavior rhythm also fluctuated with 4- to 5-day cycles and peaked primarily during proestrus or estrus. The phases of eating behavior rhythms fluctuated, but not at 4- or 5-day intervals, and phases did not correlate with estrous cycle stages. After ovariectomy, the eating behavior rhythm amplitude fluctuated at irregular intervals. In constant darkness, the amplitude of the circadian eating behavior rhythm peaked every 4 or 5 days and coincided with the circadian day that had the greatest number of wheel revolutions, a marker of proestrus. These data suggest that fluctuations of ovarian hormones across the estrous cycle temporally organize the robustness of circadian eating behavior rhythms so that it peaks during ovulation and sexual receptivity.
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This content will become publicly available on March 17, 2027
Exogenous estradiol does not regulate daily metabolic rhythms underlying diet-induced obesity in male mice
Male mice fed high-fat diet become obese, but female mice are resistant to diet-induced weight gain. We previously found that circulating estradiol in females protects their daily rhythms from disruption by high-fat feeding to prevent diet-induced obesity. The goal of this study was to determine the effects of estradiol on daily metabolic rhythms in male mice. Male C57BL/6J mice were treated with estradiol and fed high-fat diet for 2 weeks. We measured the effects of high-fat diet feeding on daily rhythms of eating behavior and locomotor activity, and on the phases, or timing, of circadian rhythms in central and peripheral tissues. We found that males treated with estradiol had lower blood glucose when fed high-fat diet than males treated with vehicle even though there were no effects of estradiol treatment on body weight and adiposity. There was no effect of estradiol on the daily rhythm of eating behavior as it was low-amplitude or arrhythmic during high-fat diet feeding in both vehicle- and estradiol-treated males. Locomotor activity rhythms were also unaffected by estradiol treatment. Likewise, the phases of circadian rhythms in the suprachiasmatic nucleus (SCN), liver, muscle, and other peripheral tissues were not altered by estradiol treatment. Thus, treatment of male mice with estradiol did not protect daily rhythms from disruption by high-fat diet, as it does in females. Together these data suggest that the mechanisms underlying sex differences in daily metabolic rhythms are complex and may require both developmental and adult exposure to hormones.
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- Award ID(s):
- 2045267
- PAR ID:
- 10679840
- Editor(s):
- Kumar, Vinay
- Publisher / Repository:
- Plos
- Date Published:
- Journal Name:
- PLOS One
- Volume:
- 21
- Issue:
- 3
- ISSN:
- 1932-6203
- Page Range / eLocation ID:
- e0343513
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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