LIVER AND PERIPHERAL TISSUE GLYCOGEN-METABOLISM IN OBESE MICE - EFFECT OF A MIXED MEAL

Glycogen metabolism in the liver, skeletal muscle, cardiac muscle, and white adipose tissue was studied in gold thioglucose (GTG) obese mice after fasting and during refeeding. Prolonged (48 h) fasted control a nd GTG mice were refed with standard laboratory diet for 24 h. During fasting and refeeding, the changes in glycogen content and the activit y of glycogen synthase I and R and phosphorylase a in the liver were s imilar in lean and GTG mice. However, the glycogen storage in the live rs from GTG mice was always greater than that in lean animals. In GTG mice-the activity of liver glycogen synthase I and R was significantly higher than that in lean animals 3 and 6 h after refeeding. The activ ity of liver phosphorylase a in GTG mice was higher than that in lean mice after refeeding. There were no significant differences in the gly cogen content of white adipose tissue, cardiac muscle, and skeletal mu scle from lean and GTG mice during the entire study. The results of th is study suggest that increased glycogen storage in the liver is a maj or alteration in nonoxidative glucose metabolism and contributes to th e development of insulin resistance and glucose intolerance in GTG obe se mice.