Lipoprotein lipase mRNA in white adipose tissue but not in skeletal muscle is increased by pioglitazone through PPAR-gamma.
Lipoprotein lipase (LPL), a key enzyme for triglyceride hydrolysis, is an insulin-dependent enzyme and mainly synthesized in white adipose tissue (WAT) and skeletal muscles (SM). To explore how pioglitazone, an enhancer of insulin action, affects LPL synthesis, we examined the effect of pioglitazone on LPL mRNA levels in WAT or SM of brown adipose tissue (BAT)-deficient mice, which develop insulin resistance and hypertriglyceridemia. Both LPL mRNA of WAT and SM were halved in BAT-deficient mice. Pioglitazone increased LPL mRNA in WAT by 8-fold, which was substantially associated with a 4-fold increase of peroxisome proliferator activated receptor (PPAR)-gamma mRNA (r=0.97, p<0.0001), whereas pioglitazone did not affect LPL mRNA in SM. These results suggest that pioglitazone exclusively increases LPL production in WAT via stimulation of PPAR-gamma synthesis. Since pioglitazone does not affect LPL production in SM, this would contribute to prevent the development of insulin resistance due to lipotoxicity.
First Department of Internal Medicine, Showa University School of Medicine, 1-5-8 Hatanodai, Shinagawa-ku, Tokyo 142-8666, Japan.
Haruaki
H
Kageyama
Tsutomu
T
Hirano
Kenta
K
Okada
Tetsu
T
Ebara
Asako
A
Kageyama
Toru
T
Murakami
Seiji
S
Shioda
Mitsuru
M
Adachi
D000273:Adipose Tissue / Q000187:drug effects / Q000378:metabolism*; D000818:Animals; D001786:Blood Glucose / Q000032:analysis; D004822:Epididymis / Q000033:anatomy & histology; D005121:Extremities / Q000033:anatomy & histology; D005786:Gene Expression Regulation; D007004:Hypoglycemic Agents / Q000494:pharmacology*; D007328:Insulin / Q000097:blood; D007473:Ion Channels; D020738:Leptin / Q000097:blood; D008071:Lipoprotein Lipase / Q000096:biosynthesis* / Q000235:genetics / Q000378:metabolism; D008297:Male; D026901:Membrane Transport Proteins; D051379:Mice; D024101:Mitochondrial Proteins; D018482:Muscle, Skeletal / Q000187:drug effects / Q000378:metabolism*; D009928:Organ Specificity; D000077205:Pioglitazone; D014176:Protein Biosynthesis; D011506:Proteins / Q000235:genetics; D012333:RNA, Messenger / Q000096:biosynthesis; D018160:Receptors, Cytoplasmic and Nuclear / Q000235:genetics / Q000378:metabolism*; D013844:Thiazoles / Q000494:pharmacology*; D045162:Thiazolidinediones; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D014280:Triglycerides / Q000097:blood; D000071246:Uncoupling Protein 2
D001786:Blood Glucose; D007004:Hypoglycemic Agents; D007328:Insulin; D007473:Ion Channels; D020738:Leptin; D026901:Membrane Transport Proteins; D024101:Mitochondrial Proteins; D011506:Proteins; D012333:RNA, Messenger; D018160:Receptors, Cytoplasmic and Nuclear; D013844:Thiazoles; D045162:Thiazolidinediones; D014157:Transcription Factors; D014280:Triglycerides; D000071246:Uncoupling Protein 2; D008071:Lipoprotein Lipase; D000077205:Pioglitazone