부산대학교 도서관

When (6-TH,6- UC)glucose was given in glucose loads to fasted rats, the average TH/ UC ratios in the glycogens deposited in their livers, relative to that in the glucoses administered, were 0.85 and 0.88. When (3-TH,3- UC)lactate was given in trace quantity along with unlabeled glucose loads, the average TH/ UC ratio in the glycogens deposited was 0.08. This indicates that a major fraction of the carbons of the glucose loads was converted to liver glycogen without first being converted to lactate. When (3-TH,6- UC)glucose was given in glucose loads, the TH/ UC ratios in the glycogens deposited averaged 0.44. This indicates that a significant amount of H bound to C-3, but not C-6, of glucose is removed within liver in the conversion of the carbons of the glucose to glycogen. This can occur in the pentose cycle and by cycling of glucose-6-P via triose phosphates. The contributions of these pathways were estimated by giving glucose loads labeled with (1- UC)glucose, (2- UC)glucose, (5- UC)glucose, and (6- UC)glucose and degrading the glucoses obtained by hydrolyzing the glycogens that deposited. Between 4 and 9% of the glucose utilized by the liver was utilized in the pentose cycle. While these are relatively small percentages a major portion of the difference between the ratios obtained with (3-TH)glucose and with (6-TH)glucose is attributable to metabolism in the pentose cycle.