title: Metabolic clearance rate is a more robust and physiological parameter for insulin sensitivity than glucose infusion rate in the isoglycemic glucose clamp technique.
abstract: BACKGROUND
  The metabolic clearance rate (MCR) of glucose has been defined as the value of the glucose infusion rate (GIR) divided by the glucose concentration and could be thus expected to be a robust marker at various glucose concentrations.
  
  
  METHODS
  We evaluated the validity of MCR compared with GIR in 15 healthy subjects and 38 type 2 diabetes patients. The glucose clamp technique was performed at two different glucose levels-isoglycemia (fasting plasma glucose [FPG]) of each subject and euglycemia (100 mg/dL), consecutively. GIR and MCR were obtained at both glucose levels, and ratios of those at isoglycemia to euglycemia were calculated.
  
  
  RESULTS
  Although there was no obvious relationship between FPG levels and GIR ratio, the MCR ratio showed a good linear regression with FPG levels (r=-0.652, P<0.0001). Furthermore, MCR at FPG was excellently (r=0.955) correlated with that at euglycemia in comparison with the modest correlation of GIR between the two plasma glucose levels (r=0.876).
  
  
  CONCLUSIONS
  GIR was rather variable and not proportional to clamped plasma glucose levels. MCR was a less variable parameter than GIR at various plasma glucose levels, and MCR at FPG in the isoglycemic clamp study could be substituted for GIR at the euglycemic clamp study.
authors.affiliation: Division of Endocrinology and Metabolism, Department of Medicine, Kurume University School of Medicine, Kurume, Japan. tajiriy@med.kurume-u.ac.jp
authors.forename: Yuji
authors.initials: Y
authors.lastname: Tajiri
authors.forename: Shuichi
authors.initials: S
authors.lastname: Sato
authors.forename: Kentaro
authors.initials: K
authors.lastname: Yamada
mesh_terms: D000328:Adult; D001786:Blood Glucose / Q000032:analysis / Q000378:metabolism*; D016009:Chi-Square Distribution; D003924:Diabetes Mellitus, Type 2 / Q000097:blood / Q000378:metabolism*; D005260:Female; D015309:Glucose Clamp Technique / Q000379:methods*; D006801:Humans; D007004:Hypoglycemic Agents / Q000008:administration & dosage; D007328:Insulin / Q000008:administration & dosage; D007333:Insulin Resistance / Q000502:physiology*; D008297:Male; D008657:Metabolic Clearance Rate; D008875:Middle Aged
chemical_list: D001786:Blood Glucose; D007004:Hypoglycemic Agents; D007328:Insulin