title: Circadian variation of granulocyte colony stimulating factor levels in man.
abstract: 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.
authors.affiliation: Department of Clinical Pharmacology, TARGET, University Hospital of Vienna, Austria. bernd.jilma@univie.ac.at
authors.forename: B
authors.initials: B
authors.lastname: Jilma
authors.forename: N
authors.initials: N
authors.lastname: Hergovich
authors.forename: P
authors.initials: P
authors.lastname: Stohlawetz
authors.forename: H G
authors.initials: HG
authors.lastname: Eichler
authors.forename: P
authors.initials: P
authors.lastname: Bauer
authors.forename: O F
authors.initials: OF
authors.lastname: Wagner
mesh_terms: 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
chemical_list: D016179:Granulocyte Colony-Stimulating Factor; D006854:Hydrocortisone