Effects of diet and exercise on muscle and liver intracellular lipid contents and insulin sensitivity in type 2 diabetic patients.
Insulin resistance is associated with the circulating free fatty acid (FFA) level and intracellular lipid content in muscle and liver. We investigated the effect of 2-wk diet and exercise therapy on total adiposity, circulating FFA, intracellular lipid content in muscle and liver, and peripheral insulin sensitivity. Type 2 diabetic patients were divided into a diet group (n = 7) and a diet plus exercise group (n = 7). We performed a hyperinsulinemic-euglycemic clamp study before and after treatment. Intramyocellular lipid (IMCL) in the tibialis anterior muscle and intrahepatic lipid (IHL) were evaluated by (1)H-magnetic resonance spectroscopy. Fasting FFA were not altered, and total body fat showed a slight, but significant, decrease in both groups after treatment. IMCL was decreased by 19%, and the glucose infusion rate was increased by 57% in the diet plus exercise group, whereas neither IMCL nor glucose infusion rate was significantly altered in the diet group. However, IHL showed a significant decrease in both groups. In summary, we found that 2 wk of diet and exercise decreased IMCL and increased muscle insulin-mediated glucose uptake, whereas diet with or without exercise decreased IHL. These effects were evident despite a small decrease in body fat and were observed independently of fasting FFA levels.
Tamura
Yoshifumi
Y
Department of Medicine, Metabolism and Endocrinology, Juntendo University School of Medicine, 2-1-1 Hongo, Bunkyo-ku, Tokyo 113-8421, Japan.
Tanaka
Yasushi
Y
Sato
Fumihiko
F
Choi
Jong Bock
JB
Watada
Hirotaka
H
Niwa
Masataka
M
Kinoshita
Junichiro
J
Ooka
Aiko
A
Kumashiro
Naoki
N
Igarashi
Yasuhiro
Y
Kyogoku
Shinsuke
S
Maehara
Tadayuki
T
Kawasumi
Masahiko
M
Hirose
Takahisa
T
Kawamori
Ryuzo
R
D001786:Blood Glucose / Q000187:drug effects / Q000378:metabolism; D015992:Body Mass Index; D003924:Diabetes Mellitus, Type 2 / Q000378:metabolism / Q000503:physiopathology*; D003927:Diet, Diabetic; D015444:Exercise / Q000502:physiology*; D005260:Female; D015309:Glucose Clamp Technique; D006442:Glycated Hemoglobin / Q000378:metabolism; D006801:Humans; D006946:Hyperinsulinism / Q000097:blood; D007328:Insulin / Q000494:pharmacology / Q000600:supply & distribution; D050356:Lipid Metabolism; D008099:Liver / Q000378:metabolism*; D008111:Liver Function Tests; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000378:metabolism*
D001786:Blood Glucose; D006442:Glycated Hemoglobin; D007328:Insulin