title: The importance of palmitoleic acid to adipocyte insulin resistance and whole-body insulin sensitivity in type 1 diabetes.
abstract: BACKGROUND
  Type 1 diabetes is an insulin-resistant state, but it is less clear which tissues are affected. Our previous report implicated skeletal muscle and liver insulin resistance in people with type 1 diabetes, but this occurred independently of generalized, visceral, or ectopic fat.
  
  
  OBJECTIVE
  The aim of the study was to measure adipose tissue insulin sensitivity and plasma triglyceride composition in individuals with type 1 diabetes after overnight insulin infusion to lower fasting glucose.
  
  
  METHODS
  Fifty subjects (25 individuals with type 1 diabetes and 25 controls without) were studied. After 3 d of dietary control and overnight insulin infusion, we performed a three-stage hyperinsulinemic/euglycemic clamp infusing insulin at 4, 8, and 40 mU/m(2) · min. Infusions of [1,1,2,3,3-(2)H(2)]glycerol and [1-(13)C]palmitate were used to quantify lipid metabolism.
  
  
  RESULTS
  Basal glycerol and palmitate rates of appearance were similar between groups, decreased more in control subjects during the first two stages of the clamp, and similarly suppressed during the highest insulin dose. The concentration of insulin required for 50% inhibition of lipolysis was twice as high in individuals with type 1 diabetes. Plasma triglyceride saturation was similar between groups, but palmitoleic acid in plasma triglyceride was inversely related to adipocyte insulin sensitivity. Unesterified palmitoleic acid in plasma was positively related to insulin sensitivity in controls, but not in individuals with type 1 diabetes.
  
  
  CONCLUSIONS
  Adipose tissue insulin resistance is a significant feature of type 1 diabetes. Palmitoleic acid is not related to insulin sensitivity in type 1 diabetes, as it was in controls, suggesting a novel mechanism for insulin resistance in this population.
authors.affiliation: Division of Endocrinology, Metabolism, and Diabetes, Department of Medicine, University of Colorado Anschutz Medical Campus, P.O. Box 6511, MS 8106, Aurora, Colorado 80045. Bryan.Bergman@ucdenver.edu
authors.forename: Bryan C
authors.initials: BC
authors.lastname: Bergman
authors.forename: David
authors.initials: D
authors.lastname: Howard
authors.forename: Irene E
authors.initials: IE
authors.lastname: Schauer
authors.forename: David M
authors.initials: DM
authors.lastname: Maahs
authors.forename: Janet K
authors.initials: JK
authors.lastname: Snell-Bergeon
authors.forename: Timothy W
authors.initials: TW
authors.lastname: Clement
authors.forename: Robert H
authors.initials: RH
authors.lastname: Eckel
authors.forename: Leigh
authors.initials: L
authors.lastname: Perreault
authors.forename: Marian
authors.initials: M
authors.lastname: Rewers
mesh_terms: D017667:Adipocytes / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D000328:Adult; D003922:Diabetes Mellitus, Type 1 / Q000097:blood / Q000178:diet therapy / Q000188:drug therapy / Q000378:metabolism*; D005229:Fatty Acids, Monounsaturated / Q000008:administration & dosage / Q000097:blood / Q000494:pharmacology*; D005260:Female; D015309:Glucose Clamp Technique; D005990:Glycerol / Q000097:blood; D006801:Humans; D007328:Insulin / Q000008:administration & dosage / Q000097:blood / Q000378:metabolism* / Q000494:pharmacology; D007333:Insulin Resistance / Q000502:physiology; D008297:Male; D008875:Middle Aged; D014280:Triglycerides / Q000097:blood; D055815:Young Adult
chemical_list: D005229:Fatty Acids, Monounsaturated; D007328:Insulin; D014280:Triglycerides; C008757:palmitoleic acid; D005990:Glycerol