title: Insulin-mediated FFA suppression is associated with triglyceridemia and insulin sensitivity independent of adiposity.
abstract: BACKGROUND
  A central/visceral fat distribution and excess free fatty acid (FFA) availability are associated with dyslipidemia and insulin resistance. However, these two characteristics often coexist, making it difficult to detect the independent contributions of each. Whether FFA suppression is more closely linked to metabolic abnormalities is not clear.
  
  
  OBJECTIVE
  The aim of the study was to examine the relationship between FFA suppression, body fat distribution, and fitness as contributors toward insulin resistance and hypertriglyceridemia.
  
  
  METHODS
  We measured systemic palmitate turnover using an iv infusion of [9,10-(3)H]palmitate; upper body sc adipose tissue (UBSQ) and visceral adipose tissue (VAT) with dual-energy x-ray absorptiometry and a single-slice abdominal computed tomography scan; fitness with a graded exercise treadmill test; and insulin sensitivity with both the iv glucose tolerance test (IVGTT) (SI(IVGTT)) and mixed meal tolerance test (SI(Meal)).
  
  
  METHODS
  The study was conducted at a General Clinical Research Center.
  
  
  METHODS
  Baseline data were obtained from 140 elderly adults (age, 60-88 yr; 83 males) and 60 young adults (age, 18-31 yr; 31 males) who participated in a previously published trial assessing the effects of 2-yr supplementation of dehydroepiandrosterone or testosterone on body composition, glucose metabolism, and bone density.
  
  
  METHODS
  There were no interventions.
  
  
  METHODS
  We measured fasting plasma triglyceride (TG) concentrations, SI(IVGTT), and SI(Meal).
  
  
  RESULTS
  Using multivariate regression analysis, the strongest combined predictors of TG concentrations were VAT, postmeal nadir FFA concentrations, sex, and age. The best predictors of SI(IVGTT) were IVGTT nadir palmitate concentration, VAT, UBSQ fat, fitness, and age, whereas the best predictors of SI(Meal) were meal nadir palmitate concentration, UBSQ fat, fitness, and sex.
  
  
  CONCLUSIONS
  FFA suppression is associated with both fasting TG concentrations and insulin sensitivity, independent of measures of adiposity.
authors.affiliation: Mayo Clinic, Endocrine Research Unit, 200 First Street SW, Room 5-194 Joseph, Rochester, Minnesota 55905, USA.
authors.forename: Nikki C
authors.initials: NC
authors.lastname: Bush
authors.forename: Rita
authors.initials: R
authors.lastname: Basu
authors.forename: Robert A
authors.initials: RA
authors.lastname: Rizza
authors.forename: K Sreekumaran
authors.initials: KS
authors.lastname: Nair
authors.forename: Sundeep
authors.initials: S
authors.lastname: Khosla
authors.forename: Michael D
authors.initials: MD
authors.lastname: Jensen
mesh_terms: D000273:Adipose Tissue / Q000000981:diagnostic imaging / Q000378:metabolism; D050154:Adiposity / Q000502:physiology*; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D050218:Body Fat Distribution; D005230:Fatty Acids, Nonesterified / Q000097:blood*; D005260:Female; D005951:Glucose Tolerance Test; D006801:Humans; D015228:Hypertriglyceridemia / Q000097:blood*; D007328:Insulin / Q000097:blood; D007333:Insulin Resistance / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000000981:diagnostic imaging / Q000378:metabolism; D011859:Radiography; D014280:Triglycerides / Q000097:blood*
chemical_list: D005230:Fatty Acids, Nonesterified; D007328:Insulin; D014280:Triglycerides