title: Leptin response to insulin in humans is related to the lipolytic state of abdominal subcutaneous fat.
abstract: Insulin-induced leptinemia in humans appears to be blunted by insulin resistance. We therefore examined the relationship between insulin action and plasma leptin by monitoring regional and whole body lipolysis and plasma leptin levels in 15 premenopausal women (body fat range, 14-59%) during a two-stage euglycemic clamp (insulin was infused 90 min each at 6-10 and 12-20 mU/m2 x min). Microdialysis probes were placed in abdominal and femoral sc adipose tissue. Subjects were given a primed, constant infusion of a stable isotope tracer (2H5-glycerol), and plasma glycerol isotope enrichments were analyzed by mass spectrometry to determine glycerol kinetics. Although there was no mean change in plasma leptin during the clamp (baseline, 16.6 +/- 4.5 ng/mL; final, 16.3 +/- 4.3 ng/mL), there was large interindividual variability in the changes in plasma leptin (range, -18% to +19%). Changes in plasma leptin during the clamp stages were correlated with abdominal dialysate glycerol concentrations (r = -0.44; P < 0.05), but not femoral dialysate glycerol concentrations (r = -0.15), the rate of appearance of glycerol in plasma (r = 0.005), or plasma insulin levels (r = 0.16). The results suggest that insulin-induced changes in plasma leptin are more related to the lipolytic state (i.e. low leptin response when lipolysis is high) of abdominal sc adipose tissue than that of other fat depots.
authors.affiliation: Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri 63110, USA.
authors.forename: J S
authors.initials: JS
authors.lastname: Fisher
authors.forename: R C
authors.initials: RC
authors.lastname: Hickner
authors.forename: S B
authors.initials: SB
authors.lastname: Racette
authors.forename: E F
authors.initials: EF
authors.lastname: Binder
authors.forename: M
authors.initials: M
authors.lastname: Landt
authors.forename: W M
authors.initials: WM
authors.lastname: Kohrt
mesh_terms: D000005:Abdomen; D000273:Adipose Tissue / Q000378:metabolism*; D000328:Adult; D001775:Blood Circulation / Q000502:physiology; D005260:Female; D005990:Glycerol / Q000097:blood; D006801:Humans; D006946:Hyperinsulinism / Q000097:blood / Q000139:chemically induced / Q000378:metabolism / Q000503:physiopathology; D007328:Insulin / Q000097:blood / Q000494:pharmacology*; D020738:Leptin / Q000097:blood*; D008066:Lipolysis; D013997:Time Factors
chemical_list: D007328:Insulin; D020738:Leptin; D005990:Glycerol