TY - JOUR
T1 - The Mechanisms by Which Both Heterozygous Peroxisome Proliferator-activated Receptor γ (PPARγ) Deficiency and PPARγ Agonist Improve Insulin Resistance
AU - Yamauchi, Toshimasa
AU - Kamon, Junji
AU - Waki, Hironori
AU - Murakami, Koji
AU - Motojima, Kiyoto
AU - Komeda, Kajuro
AU - Ide, Tomohiro
AU - Kubota, Naoto
AU - Terauchi, Yasuo
AU - Tobe, Kazuyuki
AU - Miki, Hiroshi
AU - Tsuchida, Atsuko
AU - Akanuma, Yasuo
AU - Nagai, Ryozo
AU - Kimura, Satoshi
AU - Kadowaki, Takashi
PY - 2001/11/2
Y1 - 2001/11/2
N2 - Peroxisome proliferator-activated receptor (PPAR) γ is a ligand-activated transcription factor and a member of the nuclear hormone receptor superfamily that is thought to be the master regulator of fat storage; however, the relationship between PPARγ and insulin sensitivity is highly controversial. We show here that supraphysiological activation of PPARγ by PPARγ agonist thiazolidinediones (TZD) markedly increases triglyceride (TG) content of white adipose tissue (WAT), thereby decreasing TG content of liver and muscle, leading to amelioration of insulin resistance at the expense of obesity. Moderate reduction of PPARγ activity by heterozygous PPARγ deficiency decreases TG content of WAT, skeletal muscle, and liver due to increased leptin expression and increase in fatty acid combustion and decrease in lipogenesis, thereby ameliorating high fat diet-induced obesity and insulin resistance. Moreover, although heterozygous PPARγ deficiency and TZD have opposite effects on total WAT mass, heterozygous PPARγ deficiency decreases lipogenesis in WAT, whereas TZD stimulate adipocyte differentiation and apoptosis, thereby both preventing adipocyte hypertrophy, which is associated with alleviation of insulin resistance presumably due to decreases in free fatty acids, and tumor necrosis factor α, and up-regulation of adiponectin, at least in part. We conclude that, although by different mechanisms, both heterozygous PPARγ deficiency and PPARγ agonist improve insulin resistance, which is associated with decreased TG content of muscle/liver and prevention of adipocyte hypertrophy.
AB - Peroxisome proliferator-activated receptor (PPAR) γ is a ligand-activated transcription factor and a member of the nuclear hormone receptor superfamily that is thought to be the master regulator of fat storage; however, the relationship between PPARγ and insulin sensitivity is highly controversial. We show here that supraphysiological activation of PPARγ by PPARγ agonist thiazolidinediones (TZD) markedly increases triglyceride (TG) content of white adipose tissue (WAT), thereby decreasing TG content of liver and muscle, leading to amelioration of insulin resistance at the expense of obesity. Moderate reduction of PPARγ activity by heterozygous PPARγ deficiency decreases TG content of WAT, skeletal muscle, and liver due to increased leptin expression and increase in fatty acid combustion and decrease in lipogenesis, thereby ameliorating high fat diet-induced obesity and insulin resistance. Moreover, although heterozygous PPARγ deficiency and TZD have opposite effects on total WAT mass, heterozygous PPARγ deficiency decreases lipogenesis in WAT, whereas TZD stimulate adipocyte differentiation and apoptosis, thereby both preventing adipocyte hypertrophy, which is associated with alleviation of insulin resistance presumably due to decreases in free fatty acids, and tumor necrosis factor α, and up-regulation of adiponectin, at least in part. We conclude that, although by different mechanisms, both heterozygous PPARγ deficiency and PPARγ agonist improve insulin resistance, which is associated with decreased TG content of muscle/liver and prevention of adipocyte hypertrophy.
UR - http://www.scopus.com/inward/record.url?scp=0035798713&partnerID=8YFLogxK
U2 - 10.1074/jbc.M103241200
DO - 10.1074/jbc.M103241200
M3 - 学術論文
C2 - 11533050
AN - SCOPUS:0035798713
SN - 0021-9258
VL - 276
SP - 41245
EP - 41254
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
IS - 44
ER -