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Circadian variations in the committed stem cell responsiveness to granulopoiesis inhibitory factor (chalone) in vitro

N P Aardal, O D Laerum, W R Paukovits

    Virchows Archiv. B, Cell Pathology Including Molecular Pathology
    |January 1, 1983
    PubMed

    Insights

    Human granulocyte extracts (chalones) significantly impact the daily rhythm of bone marrow colony formation. These extracts caused phase shifts and amplitude changes, with effects oscillating between inhibition and stimulation over 24 hours.

    Area of Science:

    • Hematology
    • Chronobiology
    • Cell Biology

    Background:

    • Bone marrow colony-forming unit-culture (CFUc) exhibits a robust circadian rhythm.
    • Human granulocytes produce inhibitory extracts known as chalones.

    Purpose of the Study:

    • To investigate the effect of human granulocyte chalone on the circadian rhythm of myelopoietic colony formation.
    • To determine if seasonal variations influence chalone's inhibitory effects.

    Main Methods:

    • Studied the circadian rhythm of bone marrow CFUc over one year.
    • Preincubated cells with granulocyte extracts before soft agar plating.
    • Monitored colony formation to assess rhythm modulation.

    Main Results:

    • Chalone extracts modulated the CFUc circadian rhythm, causing phase shifts and amplitude modifications.
    • The extracts' effects oscillated, showing significant inhibition and stimulation within a 24-hour period.
    • No significant seasonal variations in chalone's inhibitory effects were observed.

    Conclusions:

    • Human granulocyte chalone influences the daily rhythm of myelopoietic colony formation.
    • The modulatory effects of chalone are time-dependent within a 24-hour cycle.
    • Seasonal factors do not appear to significantly alter chalone's impact on this process.

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