title: Insulin regulation of plasma free fatty acid concentrations is abnormal in healthy subjects with muscle insulin resistance.
abstract: This study evaluated the ability of insulin to regulate free fatty acid (FFA) concentrations in healthy nondiabetic subjects selected to be either insulin-resistant or -sensitive on the basis of insulin-mediated glucose disposal by muscle. Comparisons of steady-state plasma glucose (SSPG), insulin (SSPI), and FFA concentrations were made at the end of 3 infusion periods: (1) under basal insulin conditions (approximately 10 microU/mL), (2) in response to isoproterenol-induced stimulation of lipolysis at the same basal insulin concentration, and (3) following inhibition of isoproterenol-induced lipolysis by a 2-fold increase in the insulin concentration. The results showed that steady-state FFA concentrations were significantly higher under basal conditions (360 +/- 73 v 158 +/- 36 microEq/L, P = .02), in response to isoproterenol-induced lipolysis (809 +/- 92 v433 +/- 65 microEq/L, P = .005), and following insulin inhibition of isoproterenol-induced lipolysis (309 +/- 65 v 159 +/- 37 microEq/L, P = .06). These differences were found despite the fact that SSPG concentrations were also higher in insulin-resistant individuals during all 3 infusion periods. These results demonstrate that the ability of insulin to regulate plasma FFA concentrations is impaired in healthy subjects with muscle insulin resistance, indicating that insulin-resistant individuals share defects in the ability of insulin to stimulate muscle glucose disposal and to inhibit adipose tissue lipolysis.
authors.affiliation: Department of Medicine, Stanford University School of Medicine, CA, USA.
authors.forename: F
authors.initials: F
authors.lastname: Abbasi
authors.forename: T
authors.initials: T
authors.lastname: McLaughlin
authors.forename: C
authors.initials: C
authors.lastname: Lamendola
authors.forename: G M
authors.initials: GM
authors.lastname: Reaven
mesh_terms: D000318:Adrenergic beta-Agonists / Q000494:pharmacology; D001794:Blood Pressure / Q000187:drug effects; D005230:Fatty Acids, Nonesterified / Q000097:blood*; D005260:Female; D006801:Humans; D007328:Insulin / Q000097:blood / Q000502:physiology*; D007333:Insulin Resistance / Q000502:physiology*; D007545:Isoproterenol / Q000494:pharmacology; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000378:metabolism*
chemical_list: D000318:Adrenergic beta-Agonists; D005230:Fatty Acids, Nonesterified; D007328:Insulin; D007545:Isoproterenol