title: Testosterone concentration and insulin sensitivity in young men with type 1 and type 2 diabetes.
abstract: OBJECTIVE
  Reduced testosterone, a recognized comorbidity of reduced insulin sensitivity (IS) and type 2 diabetes (T2D), has also been reported in adult males with type 1 diabetes (T1D). However, there are limited data on how early reduced testosterone occurs, and whether it is related to the reduced IS in T1D. Leptin, a modulator of the HPG-axis, may also influence testosterone in T1D. We hypothesized that IS and leptin would be associated with total testosterone (TT), and free androgen index (FAI) in adolescent males with T1D.
  
  
  METHODS
  T1D (n = 35), T2D (n = 13), lean (n = 13) and obese (n = 9) adolescent males had IS measured by hyperinsulinemic-euglycemic clamps (glucose infusion rate [GIR]), in addition to leptin, sex hormone binding globulin (SHBG), TT, and FAI. The cohort was stratified into those with T1D (n = 35) and those without (n = 35).
  
  
  RESULTS
  TT and SHBG were lower in T2D boys vs. lean controls, and GIR and leptin correlated with FAI and TT in non-T1D participants. However, despite being insulin resistant, adolescent males with T1D had normal TT and FAI, unrelated to GIR. In T1D, leptin was inversely associated with TT (p = 0.005) and FAI (p = 0.01), independent of puberty, hemoglobin A1c (HbA1c), diabetes duration, body mass index (BMI) z-score and GIR.
  
  
  CONCLUSIONS
  Leptin accounted for a significant proportion of the variability of testosterone in T1D. However, despite reduced IS, there was no association between IS and testosterone in T1D adolescents. These observations suggest that the mechanisms affecting testosterone may differ between adolescent males with and without T1D.
authors.affiliation: Department of Pediatric Endocrinology, University of Colorado Denver, Aurora, CO, USA.
authors.forename: Megan M
authors.initials: MM
authors.lastname: Kelsey
authors.affiliation: Department of Pediatrics, University of Colorado Denver, Aurora, CO, USA.
authors.forename: Petter
authors.initials: P
authors.lastname: Bjornstad
authors.affiliation: Department of Biostatistics, University of Colorado Denver, Aurora, CO, USA.
authors.forename: Kim
authors.initials: K
authors.lastname: McFann
authors.affiliation: Department of Pediatric Endocrinology, University of Colorado Denver, Aurora, CO, USA.
authors.forename: Kristen
authors.initials: K
authors.lastname: Nadeau
mesh_terms: D000293:Adolescent; D002648:Child; D015331:Cohort Studies; D003922:Diabetes Mellitus, Type 1 / Q000097:blood*; D003924:Diabetes Mellitus, Type 2 / Q000097:blood*; D015309:Glucose Clamp Technique; D006801:Humans; D007333:Insulin Resistance; D020738:Leptin / Q000097:blood*; D008297:Male; D009765:Obesity / Q000097:blood / Q000150:complications; D013739:Testosterone / Q000097:blood*
chemical_list: D020738:Leptin; D013739:Testosterone
keywords: insulin sensitivity; leptin; puberty; testosterone; type 1 diabetes