OBJECTIVE: It has been hypothesized that excessive fatty acid availability contributes to steatosis and the metabolic abnormalities associated with nonalcoholic fatty liver disease (NAFLD). The purpose of this study was to evaluate whether adipose tissue lipolytic activity and the rate of fatty acid release into plasma are increased in obese adolescents with NAFLD. METHODS: Palmitate kinetics were determined in obese adolescents with normal (n = 9; BMI = 37 +/- 2 kg/m(2); intrahepatic triglyceride (IHTG) <or=5.5% of liver volume) and increased (n = 9; BMI = 36 +/- 2 kg/m(2); IHTG >or= 10% of liver volume) IHTG content during the basal state (postabsorptive condition) and during physiological hyperinsulinemia (postprandial condition). Both groups were matched on body weight, BMI, percent body fat, age, sex, and Tanner stage. The hyperinsulinemic-euglycemic clamp procedure, in conjunction with a deuterated palmitate tracer infusion, was used to determine free-fatty acid (FFA) kinetics, and magnetic resonance spectroscopy was used to determine IHTG content. RESULTS: The rate of whole-body palmitate release into plasma was greater in subjects with NAFLD than those with normal IHTG content during basal conditions, (87 +/- 7 vs. 127 +/- 13 micromol/min; P < 0.01) and during physiological hyperinsulinemia, (24 +/- 2 vs. 44 +/- 8 micromol/min; P < 0.01). DISCUSSION: These results demonstrate that adipose tissue lipolytic activity is increased in obese adolescents with NAFLD and results in an increase in the rate of fatty acid release into plasma throughout the day. This continual excess in fatty acid flux supports the hypothesis that adipose insulin resistance is involved in the pathogenesis of steatosis and contributes to the metabolic complications associated with NAFLD.
OBJECTIVE: It has been hypothesized that excessive fatty acid availability contributes to steatosis and the metabolic abnormalities associated with nonalcoholic fatty liver disease (NAFLD). The purpose of this study was to evaluate whether adipose tissue lipolytic activity and the rate of fatty acid release into plasma are increased in obese adolescents with NAFLD. METHODS:Palmitate kinetics were determined in obese adolescents with normal (n = 9; BMI = 37 +/- 2 kg/m(2); intrahepatictriglyceride (IHTG) <or=5.5% of liver volume) and increased (n = 9; BMI = 36 +/- 2 kg/m(2); IHTG >or= 10% of liver volume) IHTG content during the basal state (postabsorptive condition) and during physiological hyperinsulinemia (postprandial condition). Both groups were matched on body weight, BMI, percent body fat, age, sex, and Tanner stage. The hyperinsulinemic-euglycemic clamp procedure, in conjunction with a deuterated palmitate tracer infusion, was used to determine free-fatty acid (FFA) kinetics, and magnetic resonance spectroscopy was used to determine IHTG content. RESULTS: The rate of whole-body palmitate release into plasma was greater in subjects with NAFLD than those with normal IHTG content during basal conditions, (87 +/- 7 vs. 127 +/- 13 micromol/min; P < 0.01) and during physiological hyperinsulinemia, (24 +/- 2 vs. 44 +/- 8 micromol/min; P < 0.01). DISCUSSION: These results demonstrate that adipose tissue lipolytic activity is increased in obese adolescents with NAFLD and results in an increase in the rate of fatty acid release into plasma throughout the day. This continual excess in fatty acid flux supports the hypothesis that adipose insulin resistance is involved in the pathogenesis of steatosis and contributes to the metabolic complications associated with NAFLD.
Authors: Chunli Yu; Yan Chen; Gary W Cline; Dongyan Zhang; Haihong Zong; Yanlin Wang; Raynald Bergeron; Jason K Kim; Samuel W Cushman; Gregory J Cooney; Bronwyn Atcheson; Morris F White; Edward W Kraegen; Gerald I Shulman Journal: J Biol Chem Date: 2002-11-14 Impact factor: 5.157
Authors: Ainara Cano; Xabier Buqué; Maite Martínez-Uña; Igor Aurrekoetxea; Ariane Menor; Juan L García-Rodríguez; Shelly C Lu; M Luz Martínez-Chantar; José M Mato; Begoña Ochoa; Patricia Aspichueta Journal: Hepatology Date: 2011-12 Impact factor: 17.425
Authors: D E Larson-Meyer; B R Newcomer; E Ravussin; J Volaufova; B Bennett; S Chalew; W T Cefalu; M Sothern Journal: Diabetologia Date: 2010-12-23 Impact factor: 10.122
Authors: Diane C Adler-Wailes; Vipul Periwal; Asem H Ali; Sheila M Brady; Jennifer R McDuffie; Gabriel I Uwaifo; Marian Tanofsky-Kraff; Christine G Salaita; Van S Hubbard; James C Reynolds; Carson C Chow; Anne E Sumner; Jack A Yanovski Journal: J Clin Endocrinol Metab Date: 2013-02-28 Impact factor: 5.958
Authors: Ebe D'Adamo; Anna M G Cali; Ram Weiss; Nicola Santoro; Bridget Pierpont; Veronika Northrup; Sonia Caprio Journal: Diabetes Care Date: 2010-08 Impact factor: 17.152