title: Effect of vitamin B12 treatment on haptocorrin.
abstract: BACKGROUND
  Haptocorrin (HC) carries the major part of circulating cobalamin, but whether HC is altered on treatment with vitamin B12 remains unknown.
  
  
  METHODS
  Our study included 3 populations: a population of vegan men (n = 174; vegan population), of whom 63 were treated daily with 5 mg of oral vitamin B12 for 3 months; a group of patients with a previous methylmalonic acid (MMA) concentration >0.4 micromol/L (n = 140; population with suspected deficiency), of which 69 were treated with weekly vitamin B12 injections (1 mg) for 4 weeks; and a subgroup of participants in a vitamin B intervention study (n = 88; nondeficient population), of whom 45 were treated daily with 0.4 mg of oral vitamin B12 for 3 months. Total HC and holoHC were measured by ELISA. Cobalamin was measured by an intrinsic factor (IF)-based assay. Samples were collected at baseline and 3 months after start of treatment.
  
  
  RESULTS
  Compared with baseline results for the 3 study populations, total HC and holoHC increased 30 pmol/L for every 100 pmol/L increase in cobalamin. After treatment with vitamin B12, holoHC (P <0.0001) and total HC (P <0.0001) increased significantly in the vegan population. Only holoHC increased in the population with suspected deficiency (P <0.0001), whereas no alteration was observed in the nondeficient population.
  
  
  CONCLUSIONS
  The HC concentration is decreased in severely cobalamin-deficient individuals and increases on treatment. The concentration of cobalamin also relates significantly to the HC concentration in nondeficient individuals.
authors.affiliation: Department of Clinical Biochemistry, Aarhus Sygehus, Denmark. almor@as.aaa.dk
authors.forename: Anne L
authors.initials: AL
authors.lastname: Mørkbak
authors.forename: Anne-Mette
authors.initials: AM
authors.lastname: Hvas
authors.forename: Zouë
authors.initials: Z
authors.lastname: Lloyd-Wright
authors.forename: Tom A B
authors.initials: TA
authors.lastname: Sanders
authors.forename: Oyvind
authors.initials: O
authors.lastname: Bleie
authors.forename: Helga
authors.initials: H
authors.lastname: Refsum
authors.forename: Ottar K
authors.initials: OK
authors.lastname: Nygaard
authors.forename: Ebba
authors.initials: E
authors.lastname: Nexø
mesh_terms: D015415:Biomarkers / Q000097:blood; D014676:Diet, Vegetarian; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012016:Reference Values; D014155:Transcobalamins / Q000378:metabolism*; D014805:Vitamin B 12 / Q000097:blood / Q000627:therapeutic use*; D014806:Vitamin B 12 Deficiency / Q000097:blood / Q000188:drug therapy*; D014803:Vitamin B Complex / Q000097:blood / Q000627:therapeutic use*
chemical_list: D015415:Biomarkers; D014155:Transcobalamins; D014803:Vitamin B Complex; D014805:Vitamin B 12