Diurnal Variation in the Glycogen Content of Human Liver Using ¹³C-MRS
【Supercategory：7. DESCENTE SPORTS SCIENCE Subcategory：7.39 Vol.39】
ABSTRACT
Carbohydrate is stored as glycogen in the liver and muscle, and it is an important energy source for endurance exercise. The roles of liver and muscle glycogen were different: the former contributes to maintain whole body blood glucose while the latter provides energy to contract muscle fiber. Our previous study demonstrated that the diurnal variation of the glycogen content in human thigh muscle was relatively small. On the other hand, there were few studies that addressed the diurnal variation of the liver glycogen. Since the liver glycogen continues to supply glucose even while sleeping, there is the possibility that the liver glycogen shows larger diurnal variation than the muscle. The purpose of this study was to investigate and compare the diurnal variation in the glycogen content of the liver and muscle using carbon magnetic resonance spectroscopy (¹³C-MRS).Five healthy male were recruited to the present study after providing written informed consent. They were instructed to maintain sedentary and to refrain from performing exercise during experiment. Three meals prior to first measurement and two meals during study were individually standardized according to the estimated energy requirement for Japanese. The liver and calf muscle (gastrocnemius + soleus muscles) glycogen content were determined noninvasively by ¹³C-MRS using a clinical MR system at 3-T. ¹³C-MRS was performed after supper on the first day, and every 3 hours from 0700h to 1900h on the second day. The changes in the muscle glycogen concentration were small through an experimental period. The larger diurnal variation of the liver glycogen content was shown: the lowest value was observed early in the morning (at 0700h). The reason for it is thought to be that the turnover rate of glycogen metabolism in the liver is faster than that in the muscle, and that a relatively long time has passed from the last meal (supper) to the next morning. The present study reveals the different diurnal variation in the glycogen content between the liver and muscle in human using ¹³C-MRS.
DESCENTE SPORTS SCIENCE Vol.39/THE DESCENTE AND ISHIMOTO MEMORIAL FOUNDATION FOR THE PROMOTION SPORTS SCIENCE
Carbohydrate is stored as glycogen in the liver and muscle, and it is an important energy source for endurance exercise. The roles of liver and muscle glycogen were different: the former contributes to maintain whole body blood glucose while the latter provides energy to contract muscle fiber. Our previous study demonstrated that the diurnal variation of the glycogen content in human thigh muscle was relatively small. On the other hand, there were few studies that addressed the diurnal variation of the liver glycogen. Since the liver glycogen continues to supply glucose even while sleeping, there is the possibility that the liver glycogen shows larger diurnal variation than the muscle. The purpose of this study was to investigate and compare the diurnal variation in the glycogen content of the liver and muscle using carbon magnetic resonance spectroscopy (¹³C-MRS).Five healthy male were recruited to the present study after providing written informed consent. They were instructed to maintain sedentary and to refrain from performing exercise during experiment. Three meals prior to first measurement and two meals during study were individually standardized according to the estimated energy requirement for Japanese. The liver and calf muscle (gastrocnemius + soleus muscles) glycogen content were determined noninvasively by ¹³C-MRS using a clinical MR system at 3-T. ¹³C-MRS was performed after supper on the first day, and every 3 hours from 0700h to 1900h on the second day. The changes in the muscle glycogen concentration were small through an experimental period. The larger diurnal variation of the liver glycogen content was shown: the lowest value was observed early in the morning (at 0700h). The reason for it is thought to be that the turnover rate of glycogen metabolism in the liver is faster than that in the muscle, and that a relatively long time has passed from the last meal (supper) to the next morning. The present study reveals the different diurnal variation in the glycogen content between the liver and muscle in human using ¹³C-MRS.
DESCENTE SPORTS SCIENCE Vol.39/THE DESCENTE AND ISHIMOTO MEMORIAL FOUNDATION FOR THE PROMOTION SPORTS SCIENCE
| Researcher | Kaito Iwayama, Hideyuki Takahashi |
|---|---|
| University or institution | Japan Institute of Sport Sciences |
Keywords
muscle glycogen, liver glycogen, 13C-MRS, carbohydrate, diurnal variation