title: Effects of thyroid hormone and hypoxia on 2,3-bisphosphoglycerate, bisphosphoglycerate synthase and phosphoglycerate mutase in rabbit erythroblasts and reticulocytes in vivo.
abstract: OBJECTIVE
  The effects of triiodothyronine (T(3)) and hypoxia on 2,3-bisphosphoglycerate (2,3-BPG) studied in vitro are unclear. To clarify these effects we selected a more physiologic approach: the in vivo study in rabbits. We also present the changes produced by T(3) and hypoxia on phosphoglycerate mutase (PGAM), which requires 2,3-BPG as a cofactor, and 2,3-BPG synthase (BPGS), the enzyme responsible for 2,3-BPG synthesis in erythroblasts and reticulocytes.
  
  
  METHODS
  Hyperthyroidism was induced by daily T(3) injection (250 microg/kg), hypoxia by a mixture of 90% nitrogen and 10% oxygen and hypothyroidism by propylthiouracil (PTU) added to drinking water.
  
  
  RESULTS
  Both T(3) administration and hypoxic conditions increased 2,3-BPG levels and BPGS mRNA levels and activity in erythroblasts but not in reticulocytes. Unlike BPGS, both PGAM mRNA levels and activity were increased in erythroblasts and reticulocytes under hyperthyrodism and hypoxia. The antihormone PTU produced opposite effects to T(3).
  
  
  CONCLUSIONS
  The results presented here suggest that both hyperthyroidism and hypoxia modulate in vivo red cell 2,3-BPG content by changes in the expression of BPGS. Similarly, the changes in PGAM activity are also explained by changes in its expression.
authors.affiliation: Unitat de Bioquímica, Departament de Ciéncies Fisiològiques I, Institut d'Investigacions Biomèdiques August Pi i Sunyer, Universitat de Barcelona, Barcelona, Spain.
authors.forename: Nuria
authors.initials: N
authors.lastname: González-Cinca
authors.forename: Pablo
authors.initials: P
authors.lastname: Pérez de la Ossa
authors.forename: José
authors.initials: J
authors.lastname: Carreras
authors.forename: Fernando
authors.initials: F
authors.lastname: Climent
mesh_terms: D019794:2,3-Diphosphoglycerate / Q000097:blood / Q000378:metabolism*; D000818:Animals; D001731:Bisphosphoglycerate Mutase / Q000097:blood / Q000235:genetics / Q000378:metabolism*; D004900:Erythroblasts / Q000378:metabolism*; D006980:Hyperthyroidism / Q000097:blood / Q000139:chemically induced / Q000378:metabolism; D000860:Hypoxia / Q000097:blood / Q000378:metabolism*; D008297:Male; D010736:Phosphoglycerate Mutase / Q000097:blood / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000097:blood / Q000378:metabolism; D011817:Rabbits; D012156:Reticulocytes / Q000378:metabolism*; D014284:Triiodothyronine / Q000494:pharmacology*
chemical_list: D012333:RNA, Messenger; D014284:Triiodothyronine; D019794:2,3-Diphosphoglycerate; D010736:Phosphoglycerate Mutase; D001731:Bisphosphoglycerate Mutase