TY - JOUR
T1 - Novel form of lipolysis induced by leptin
AU - Wang, May-Yun
AU - Lee, Young H
AU - Unger, Roger H
PY - 1999/6/18
Y1 - 1999/6/18
N2 - Hyperleptinemia causes disappearance of body fat without a rise in free fatty acids (FFA) or ketones, suggesting that leptin can deplete adipocytes of fat without releasing FFA. To test this, we measured FFA and glycerol released from adipocytes obtained from normal lean Zucker diabetic fatty rats (+/+) and incubated for 0, 3, 6, or 24 h in either 20 ng]ml recombinant leptin or 100 nM norepinephrine (NE). Whereas NE increased both FFA and glycerol release from adipocytes of +/+ rats, leptin increased glycerol release in +/+ adipocytes without a parallel increase in FFA release. In adipocytes of obese Zucker diabetic fatty rats (fe/fa) with defective leptin receptors, NE increased both FFA and glycerol release, but leptin had no effect on either. Leptin significantly lowered the mRNA of leptin and fatty acid synthase of adipocytes (FAS) (p < 0.05), and up-regulated the mRNA of peroxisome proliferator-activated receptor (PPAR)-α, carnitine palmitoyl transferase-1, (CPT-1), and acyl CoA oxidase (ACO) (p < 0.05). NE (100 nM) also lowered leptin mRNA (p < 0.05) but did not affect FAS, PPARα, ACO, or CPT-1 expression. We conclude that in normal adipocytes leptin directly decreases FAS expression, increases PPARα and the enzymes of FFA oxidation, and stimulates a novel form of lipolysis in which glycerol is released without a proportional release of FFA.
AB - Hyperleptinemia causes disappearance of body fat without a rise in free fatty acids (FFA) or ketones, suggesting that leptin can deplete adipocytes of fat without releasing FFA. To test this, we measured FFA and glycerol released from adipocytes obtained from normal lean Zucker diabetic fatty rats (+/+) and incubated for 0, 3, 6, or 24 h in either 20 ng]ml recombinant leptin or 100 nM norepinephrine (NE). Whereas NE increased both FFA and glycerol release from adipocytes of +/+ rats, leptin increased glycerol release in +/+ adipocytes without a parallel increase in FFA release. In adipocytes of obese Zucker diabetic fatty rats (fe/fa) with defective leptin receptors, NE increased both FFA and glycerol release, but leptin had no effect on either. Leptin significantly lowered the mRNA of leptin and fatty acid synthase of adipocytes (FAS) (p < 0.05), and up-regulated the mRNA of peroxisome proliferator-activated receptor (PPAR)-α, carnitine palmitoyl transferase-1, (CPT-1), and acyl CoA oxidase (ACO) (p < 0.05). NE (100 nM) also lowered leptin mRNA (p < 0.05) but did not affect FAS, PPARα, ACO, or CPT-1 expression. We conclude that in normal adipocytes leptin directly decreases FAS expression, increases PPARα and the enzymes of FFA oxidation, and stimulates a novel form of lipolysis in which glycerol is released without a proportional release of FFA.
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U2 - 10.1074/jbc.274.25.17541
DO - 10.1074/jbc.274.25.17541
M3 - Article
C2 - 10364187
AN - SCOPUS:0033580938
SN - 0021-9258
VL - 274
SP - 17541
EP - 17544
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
IS - 25
ER -