title: EPO, red cells, and serum transferrin receptor in continuous and intermittent hypoxia.
abstract: OBJECTIVE
  Erythropoietic response in 10 healthy nonsmoking volunteers exposed to normobaric hypoxia continuously or intermittently 12 h daily for 7 d was evaluated in a randomized cross-over study.
  
  
  METHODS
  An oxygen content of 15.4% corresponding to an altitude of 2500 m was created by adding nitrogen into room air in a flat. Venous blood samples for hemoglobin (Hb), hematocrit (Hct), reticulocytes, serum erythropoietin (S-EPO), red cell 2,3-diphosphoglycerate (2,3-DPG), serum ferritin (S-Ferrit), and serum soluble transferrin receptor (S-TransfR) were drawn at 8:00 a.m.
  
  
  RESULTS
  S-EPO was increased from baseline values of 22.9+/-9.6 and 20.5+/-10.1 U x L(-1) to 40.7+/-12.9 (P < 0.05) and 35+/-14.3 U x L(-1) (P < 0.05) after the first night in continuous and intermittent hypoxia, respectively, and remained elevated throughout both exposures. Hb and Hct values did not show any significant changes. Red cell 2,3-DPG rose from baseline a value of 5.0+/-0.8 to 5.9+/-0.7 mmol x L(-1) (P < 0.05) after the first day in continuous hypoxia and from 5.2+/-0.7 mmol x L(-1) to 6.1+/-0.5 mmol x L(-1) on day 3 (P < 0.05) during intermittent hypoxia. The reticulocyte count rose significantly (P < 0.05) after 5 d in both experiments. S-transferrin receptor level rose significantly from 2.2+/-0.4 and 2.1+/-0.5 mg x L(-1) to 2.6+/-0.5 mg x L(-1) and 2.3+/-0.6 mg x L(-1) on day 5 (P < 0.05), to 2.7+/-0.5 mg x L(-1) and 2.5+/-0.6 mg x L(-1) on day 7 (P < 0.05) under continuous and intermittent hypoxia, respectively.
  
  
  CONCLUSIONS
  We suggest that intermittent exposure to moderate normobaric hypoxia 12 h daily for 1 wk induces a similar stimulation of erythropoiesis as continuous exposure.
authors.affiliation: Health Center Hospital of Oulu, Finland. Pentti.Koistinen@ouka.fi
authors.forename: P O
authors.initials: PO
authors.lastname: Koistinen
authors.forename: H
authors.initials: H
authors.lastname: Rusko
authors.forename: K
authors.initials: K
authors.lastname: Irjala
authors.forename: A
authors.initials: A
authors.lastname: Rajamäki
authors.forename: K
authors.initials: K
authors.lastname: Penttinen
authors.forename: V P
authors.initials: VP
authors.lastname: Sarparanta
authors.forename: J
authors.initials: J
authors.lastname: Karpakka
authors.forename: J
authors.initials: J
authors.lastname: Leppäluoto
mesh_terms: D000328:Adult; D018592:Cross-Over Studies; D004912:Erythrocytes; D004921:Erythropoietin / Q000097:blood*; D005260:Female; D006801:Humans; D000860:Hypoxia / Q000097:blood*; D008297:Male; D011897:Random Allocation; D011990:Receptors, Transferrin / Q000097:blood*
chemical_list: D011990:Receptors, Transferrin; D004921:Erythropoietin