Effect of fasting on PPARgamma and AMPK activity in adipocytes.
We investigated the effects of fasting on gene expression and intracellular signals regulating energy metabolism in adipose tissue. Following fasting for 15h or 39h, epididymal fat pads were isolated from Wistar rats. PPARgamma mRNA levels decreased in the adipose tissues isolated from rats fasted for 39h, whereas adipocyte lipid-binding protein (aP2) and lipoprotein lipase (LPL) mRNA levels increased. Overnight fasting increased the AMP/ATP ratio and AMP-activated protein kinase (AMPK) in adipose tissue, but not in muscle or liver tissue. In addition, the effect of 5-aminoimidazole-4-carboxyamide-ribonucleoside (AICAR) on PPARgamma expression in primary cultured adipocytes was investigated. AICAR reduced PPARgamma mRNA levels but increased aP2 and LPL mRNA levels. Thus, fasting-induced AMPK activation may affect on the regulation of gene expression in adipocytes.
Kajita
Kazuo
K
Department of General Internal Medicine, Gifu University Graduate School of Medicine, Yanagido 1-1, Gifu 501-1194, Japan.
Mune
Tomoatsu
T
Ikeda
Takahide
T
Matsumoto
Masami
M
Uno
Yoshihiro
Y
Sugiyama
Chiyo
C
Matsubara
Kenji
K
Morita
Hiroyuki
H
Takemura
Masao
M
Seishima
Mitsuru
M
Takeda
Jun
J
Ishizuka
Tatsuo
T
D000263:Adenylate Kinase / Q000235:genetics*; D017667:Adipocytes / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism*; D000273:Adipose Tissue / Q000378:metabolism; D000620:Aminoimidazole Carboxamide / Q000031:analogs & derivatives / Q000494:pharmacology; D000818:Animals; D004734:Energy Metabolism; D005215:Fasting; D008297:Male; D047495:PPAR gamma / Q000235:genetics*; D051381:Rats; D017208:Rats, Wistar; D012265:Ribonucleotides / Q000494:pharmacology
D047495:PPAR gamma; D012265:Ribonucleotides; D000620:Aminoimidazole Carboxamide; D000263:Adenylate Kinase; C031143:AICA ribonucleotide