title: Hyperinsulinemia in individuals with obesity: Role of insulin clearance.
abstract: OBJECTIVE
  Several studies have shown decreased insulin clearance rate (ICR) in individuals with obesity, but it remains unclear whether this is predominately due to obesity-associated insulin resistance (IR) or obesity itself. This study aimed to clarify the complex interrelationship that exists between obesity, IR, and ICR.
  
  
  METHODS
  Healthy volunteers (n = 277) had measurement of IR and ICR using the insulin suppression test (IST). IR was quantified by determining the steady-state plasma glucose (SSPG) during the IST. ICR was estimated by dividing the insulin infusion rate by the steady-state plasma insulin concentration. We performed our analysis by stratifying the experimental population into four dichotomous categories, varying in obesity and IR. Obesity was defined as a body mass index (BMI) ≥ 30 kg/m(2) , and IR was defined as SSPG ≥ 150 mg/dL.
  
  
  RESULTS
  Individuals with obesity had higher fasting insulin compared with individuals without obesity, regardless of IR. ICR was similar between individuals with and without obesity but was higher in insulin resistant individuals compared with insulin-sensitive individuals. In multivariate analysis, both fasting insulin and SSPG were significantly associated with ICR. No significant relationships were observed between BMI and ICR.
  
  
  CONCLUSIONS
  Reduced ICR in obesity is secondary to IR, not excess adiposity.
authors.affiliation: Division of Endocrinology and Metabolism, Department of Internal Medicine, the Catholic University of Korea, Seoul, Korea.
authors.forename: Mee Kyoung
authors.initials: MK
authors.lastname: Kim
authors.affiliation: Department of Medicine, Stanford University School of Medicine, Stanford, California, USA.
authors.forename: Gerald M
authors.initials: GM
authors.lastname: Reaven
authors.affiliation: Department of Pediatrics and Medicine, UCLA School of Medicine, Institute for Translational Genomics and Population Sciences, LAbiomedical Research Institute, Harbor-UCLA Medical Center, Los Angeles, USA.
authors.forename: Yii-Der Ida
authors.initials: YD
authors.lastname: Chen
authors.affiliation: Department of Pediatrics and Medicine, UCLA School of Medicine, Institute for Translational Genomics and Population Sciences, LAbiomedical Research Institute, Harbor-UCLA Medical Center, Los Angeles, USA.
authors.forename: Eric
authors.initials: E
authors.lastname: Kim
authors.affiliation: Department of Medicine, Stanford University School of Medicine, Stanford, California, USA.
authors.forename: Sun H
authors.initials: SH
authors.lastname: Kim
mesh_terms: D000328:Adult; D001786:Blood Glucose / Q000032:analysis; D015992:Body Mass Index; D005215:Fasting / Q000097:blood; D005260:Female; D064368:Healthy Volunteers; D006801:Humans; D006946:Hyperinsulinism / Q000097:blood* / Q000209:etiology; D007328:Insulin / Q000008:administration & dosage / Q000097:blood*; D007333:Insulin Resistance / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000097:blood / Q000150:complications*
chemical_list: D001786:Blood Glucose; D007328:Insulin