title: Insulin regulation of regional free fatty acid metabolism.
abstract: Studies were conducted to determine whether regional free fatty acid (FFA) release is differentially regulated by insulin. Systemic, leg, and splanchnic palmitate rate of appearance ([9,10-(3)H]palmitate) was measured in 26 healthy adults using the euglycemic-hyperinsulinemic clamp technique to achieve a physiological range of plasma insulin concentrations. We found that insulin inhibited systemic, leg, and splanchnic palmitate release in a dose-dependent fashion over the range of insulin infused (0-1.0 mU x kg(-1) x min(-1)). Progressive hyperinsulinemia changed the leg from a net producer to a net FFA consumer, whereas the splanchnic bed converted from a net FFA consumer to a net producer. At the 0.5 mU x kg(-1) x min(-1) insulin infusion rate, leg FFA release was almost completely suppressed, whereas even with the 1.0 mU x kg(-1) x min(-1) insulin infusion rate, splanchnic FFA release decreased by only approximately 65% (P < 0.05 leg vs. splanchnic). These results demonstrate the regional heterogeneity of insulin-regulated FFA release in vivo, and indicate that visceral adipose tissue lipolysis is more resistant to insulin suppression than is leg lipolysis in humans.
authors.affiliation: Endocrine Research Unit, Mayo Clinic, Rochester, Minnesota 55905, USA.
authors.forename: S E
authors.initials: SE
authors.lastname: Meek
authors.forename: K S
authors.initials: KS
authors.lastname: Nair
authors.forename: M D
authors.initials: MD
authors.lastname: Jensen
mesh_terms: D000328:Adult; D002395:Catecholamines / Q000097:blood; D004305:Dose-Response Relationship, Drug; D005230:Fatty Acids, Nonesterified / Q000378:metabolism*; D005260:Female; D006801:Humans; D007328:Insulin / Q000097:blood / Q000494:pharmacology*; D007700:Kinetics; D007866:Leg / Q000098:blood supply; D008297:Male; D009994:Osmolar Concentration; D010168:Palmitates / Q000097:blood; D012016:Reference Values; D013152:Splanchnic Circulation / Q000502:physiology
chemical_list: D002395:Catecholamines; D005230:Fatty Acids, Nonesterified; D007328:Insulin; D010168:Palmitates