Similar Patterns of Period1 Gene Activity in Two Types of Human Blood Cells

Significant daily variations in hPer1 expression were observed in peripheral blood cells from seven healthy young male volunteers.

• hPer1 expression in peripheral mononuclear cells and polymorphonuclear neutrophils showed similar patterns of daily variation.
• Peak transcription of hPer1 occurred in the subjective morning among the participants.
• The timing of hPer1 expression rhythms in both cell types positively correlated with serum melatonin secretion rhythms.
• These findings suggest that the regulation of clock gene activity may be consistent across different types of peripheral blood cells.
• The results support the idea that the suprachiasmatic nucleus influences peripheral biological clocks.

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