title: Metabolism of insulin glargine after repeated daily subcutaneous injections in subjects with type 2 diabetes.
abstract: OBJECTIVE
  To investigate concentration of plasma insulin glargine after its subcutaneous dosing compared with concentration of its metabolites 1 (M1) and 2 (M2) in subjects with type 2 diabetes.
  
  
  METHODS
  Nine subjects underwent a 32-h euglycemic glucose clamp study (0.4 units/kg glargine after 1 week of daily glargine administration). Glargine, M1, and M2 were measured by a specific liquid chromatography-tandem mass spectrometry assay.
  
  
  RESULTS
  Glargine was detected in only five of the nine subjects, at few time points, and at negligible concentrations. M1 was detected in all subjects and exhibited the same pattern as traditional radioimmunoassay-measured plasma insulin. M2 was not detected at all.
  
  
  CONCLUSIONS
  After subcutaneous injection, glargine was minimally detectable in blood, whereas its metabolite M1 accounted for most (>90%) of the plasma insulin concentration and metabolic action of the injected glargine.
authors.affiliation: Internal Medicine, University of Perugia, Perugia, Italy.
authors.forename: Paola
authors.initials: P
authors.lastname: Lucidi
authors.forename: Francesca
authors.initials: F
authors.lastname: Porcellati
authors.forename: Paolo
authors.initials: P
authors.lastname: Rossetti
authors.forename: Paola
authors.initials: P
authors.lastname: Candeloro
authors.forename: Anna Marinelli
authors.initials: AM
authors.lastname: Andreoli
authors.forename: Patrizia
authors.initials: P
authors.lastname: Cioli
authors.forename: Annke
authors.initials: A
authors.lastname: Hahn
authors.forename: Ronald
authors.initials: R
authors.lastname: Schmidt
authors.forename: Geremia B
authors.initials: GB
authors.lastname: Bolli
authors.forename: Carmine G
authors.initials: CG
authors.lastname: Fanelli
mesh_terms: D000368:Aged; D001786:Blood Glucose / Q000378:metabolism; D003924:Diabetes Mellitus, Type 2 / Q000188:drug therapy* / Q000378:metabolism*; D005260:Female; D006801:Humans; D007004:Hypoglycemic Agents / Q000008:administration & dosage / Q000493:pharmacokinetics; D007279:Injections, Subcutaneous; D000069036:Insulin Glargine; D049528:Insulin, Long-Acting / Q000008:administration & dosage* / Q000493:pharmacokinetics*; D008297:Male; D008875:Middle Aged
chemical_list: D001786:Blood Glucose; D007004:Hypoglycemic Agents; D049528:Insulin, Long-Acting; D000069036:Insulin Glargine