Circadian variation of granulocyte colony stimulating factor levels in man.
Glucocorticoids dose-dependently increase plasma levels of granulocyte colony stimulating factor (G-CSF). Based on the marked circadian rhythm of cortisol levels, we hypothesized that plasma levels of G-CSF may also show a diurnal rhythm. A prospective study was conducted in 12 healthy young volunteers. Blood samples were obtained every 2 h over 24 h. G-CSF levels averaged 18.0 ng/l (CI 13. 1-22.9) at 8.00 am, increased continuously and reached peak values at 10.00 p.m. Individual harmonic regression analysis showed a clear circadian rhythm. The individual differences between nadir and peak levels averaged 54% (CI 43-65%). This pronounced diurnal rhythm of G-CSF levels may help understand the circadian changes in circulating stem cells, bone marrow DNA synthesis, or bone marrow toxicity induced by some chemotherapeutic agents.
Jilma
B
B
Department of Clinical Pharmacology, TARGET, University Hospital of Vienna, Austria. bernd.jilma@univie.ac.at
Hergovich
N
N
Stohlawetz
P
P
Eichler
H G
HG
Bauer
P
P
Wagner
O F
OF
D000328:Adult; D002940:Circadian Rhythm; D016179:Granulocyte Colony-Stimulating Factor / Q000378:metabolism*; D006801:Humans; D006854:Hydrocortisone / Q000378:metabolism; D009504:Neutrophils / Q000502:physiology; D011446:Prospective Studies
D016179:Granulocyte Colony-Stimulating Factor; D006854:Hydrocortisone