Effects of Diet and Exercise on Muscle and Liver Intracellular Lipid Contents and Insulin Sensitivity in Type 2 Diabetic Patients

• Published in: The journal of clinical endocrinology and metabolism 2005-06, Vol.90 (6), p.3191-3196
• Main Authors: Tamura, Yoshifumi, Tanaka, Yasushi, Sato, Fumihiko, Choi, Jong Bock, Watada, Hirotaka, Niwa, Masataka, Kinoshita, Junichiro, Ooka, Aiko, Kumashiro, Naoki, Igarashi, Yasuhiro, Kyogoku, Shinsuke, Maehara, Tadayuki, Kawasumi, Masahiko, Hirose, Takahisa, Kawamori, Ryuzo
• Format: Article
• Language: English
• Subjects: Biological and medical sciences; Blood Glucose - drug effects; Blood Glucose - metabolism; Body Mass Index; Diabetes Mellitus, Type 2 - metabolism; Diabetes Mellitus, Type 2 - physiopathology; Diet, Diabetic; Endocrinopathies; Exercise - physiology; Female; Fundamental and applied biological sciences. Psychology; Glucose Clamp Technique; Glycated Hemoglobin A - metabolism; Humans; Hyperinsulinism - blood; Insulin - pharmacology; Insulin - supply & distribution; Lipid Metabolism; Liver - metabolism; Liver Function Tests; Male; Medical sciences; Middle Aged; Muscle, Skeletal - metabolism; Vertebrates: endocrinology
• ISSN: 0021-972X; 1945-7197
• DOI: 10.1210/jc.2004-1959

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 1H-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.