Changes in day length affect the body clock and fat metabolism in rats

Rats exposed to short-day conditions exhibited significant increases in serum triglyceride levels and body weight compared to those in long-day conditions.

• Altered photoperiods disrupted the rhythmicity of circadian clocks and shifted phase values of clock genes.
• Short-day conditions were associated with more pronounced changes in physiological outputs related to lipid metabolism.
• Increased serum levels of triglycerides, high-density lipoprotein, and leptin were observed in rats under short-day conditions.
• Short-day exposure led to a higher fat:weight ratio and increased hepatic triglyceride levels.
• The observed metabolic changes may be linked to upregulated expression of specific genes involved in lipid metabolism.

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