Anti-obesity actions of green tea: possible involvements in modulation of the glucose uptake system and suppression of the adipogenesis-related transcription factors.
To investigate mechanisms of the anti-obesity actions of green tea in vivo, rats were given green tea instead of drinking water for 3 weeks. It was confirmed that green tea reduced adipose tissue weight without any change in body weight, other tissue weights, and food and water intakes. Green tea also significantly reduced the plasma levels of cholesterols and free fatty acids. Certain catechins existed in the plasma at 0.24 microM under our experimental conditions, though most of them existed as conjugated forms. For mechanisms of the anti-obesity actions, green tea significantly reduced glucose uptake accompanied by a decrease in translocation of glucose transporter 4 (GLUT4) in adipose tissue, while it significantly stimulated the glucose uptake with GLUT4 translocation in skeletal muscle. Moreover, green tea suppressed the expression of peroxisome proliferator-activated receptor gamma and the activation of sterol regulatory element binding protein-1 in adipose tissue. In conclusion, green tea modulates the glucose uptake system in adipose tissue and skeletal muscle and suppresses the expression and/or activation of adipogenesis-related transcription factors, as the possible mechanisms of its anti-obesity actions.
Ashida
Hitoshi
H
Department of Biofunctional Chemistry, Faculty of Agriculture, Kobe University, Rokkodai, Nada-ku, Kobe 657-8501, Japan. ashida@kobe-u.ac.jp
Furuyashiki
Takashi
T
Nagayasu
Hironobu
H
Bessho
Hiroaki
H
Sakakibara
Hiroyuki
H
Hashimoto
Takashi
T
Kanazawa
Kazuki
K
D000273:Adipose Tissue / Q000033:anatomy & histology / Q000187:drug effects*; D000818:Animals; D019440:Anti-Obesity Agents / Q000494:pharmacology*; D001692:Biological Transport / Q000187:drug effects; D001835:Body Weight / Q000187:drug effects; D005947:Glucose / Q000378:metabolism*; D020738:Leptin / Q000097:blood; D008055:Lipids / Q000097:blood; D008297:Male; D009929:Organ Size / Q000187:drug effects; D008517:Phytotherapy; D010936:Plant Extracts / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D013662:Tea; D014157:Transcription Factors / Q000037:antagonists & inhibitors / Q000187:drug effects*
D019440:Anti-Obesity Agents; D020738:Leptin; D008055:Lipids; D010936:Plant Extracts; D013662:Tea; D014157:Transcription Factors; D005947:Glucose