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Comparison between diurnal changes and changes induced by hydrocortisone and epinephrine in circulating myeloid

Insights

Daily fluctuations in myeloid progenitor cells (CFU-GM) and polymorphonuclear leukocytes (PMN) are correlated. These diurnal changes in blood cell counts appear to be influenced by epinephrine, suggesting a shift between blood compartments.

Area of Science:

  • Hematology
  • Immunology
  • Chronobiology

Background:

  • Blood cell concentrations exhibit diurnal variations.
  • Myeloid progenitor cells (CFU-GM) and polymorphonuclear leukocytes (PMN) are key components of the immune system.
  • Understanding diurnal patterns is crucial for interpreting hematological data.

Purpose of the Study:

  • To investigate the diurnal changes in blood concentrations of CFU-GM and PMN in healthy individuals.
  • To compare spontaneous diurnal variations with those induced by hydrocortisone and epinephrine.
  • To elucidate the mechanisms underlying diurnal blood cell count fluctuations.

Main Methods:

  • Studied 45 healthy subjects for diurnal blood concentration changes of CFU-GM and PMN.
  • Administered intravenous hydrocortisone to 16 volunteers and epinephrine to 10 volunteers.
  • Correlated spontaneous diurnal changes with induced changes.

Main Results:

  • Significant increases in both CFU-GM and PMN blood concentrations were observed from 8 AM to 3 PM.
  • Diurnal changes in CFU-GM and PMN were significantly correlated.
  • Induced changes by epinephrine administration mimicked spontaneous diurnal patterns.

Conclusions:

  • Diurnal variations in blood CFU-GM and PMN levels are significant and correlated.
  • Epinephrine administration appears to influence these diurnal patterns.
  • Findings suggest diurnal changes in CFU-GM primarily reflect cell shifts between blood compartments.

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