Dim Night Light May Affect Eating and Weight Gain in Growing Mice

Exposure to dim light at night (dLAN) beginning at 5 weeks of age is associated with increased body mass and daytime food intake in male mice.

• Young mice exposed to dLAN starting at 3 weeks of age showed no significant differences in growth rates or body mass compared to those raised in standard light-dark cycles.
• Male mice exposed to dLAN beginning at 5 weeks displayed increased body mass and daytime food intake, while female mice did not show these changes.
• Clock gene expression in the liver remained unchanged despite the increased body mass associated with dLAN exposure.
• The effects of dLAN on body mass gain may depend on the age of exposure and the sex of the mice.

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