1H-MRS STUDY ON GENDER DIFFERENCES IN INTRAMUSCULAR TRIGLYCERIDES IN HUMAN SKELETAL MUSCLE AND THEIR RELATION TO BODY FAT AND ENDURANCE CAPACITY / 体力科学

ABSTRACT

Gender differences were measured in the amount of intramyocellular triglyceride (IMCL) and extramyocellular triglyceride (EMCL) in skeletal muscles using<SUP>1</SUP>H-MR spectroscopy and their relation to body fat and peak VO<SUB>2</SUB>was studied. Fourteen apparently healthy subjects were separated into groups by gender. Both the male and female group subjects were selected according to similar ages and BMI (male n=7, BMI=20.5±0.6 kg/m<SUP>2</SUP>, age=21.1±0.7 years, female n=7, BMI=20.6±0.5 kg/m<SUP>2</SUP>, age=18.7±0.3 years) . We found a significant correlation between IMCL and EMCL in the soleus (SQL p<0.01) and medial gastrocnemius (MG p<0.01) muscles. IMCL values in SQL were significantly higher than IMCL values in MG and tibialis anterior muscle (TA) in both males and females in the order of SQL>MG>TA (p<0.01) .<BR>IMCL and EMCL values in MG and SQL among females were significantly higher (p<0.01) than their corresponding values in males. However, a gender difference in IMCL and EMCL values for TA was not found. There was no correlation between IMCL and EMCL values for each muscle and BMI ; but IMCL (r=0.63 in SQL) and EMCL (r=0.88 and r=0.73 in SQL, and MG, respectively; p< 0.01) values correlated significantly with percent FAT. There was no correlation between IMCL values for each muscle and peak VO<SUB>2</SUB>; but the EMCL values of SQL correlated quite negatively with peak VO<SUB>2</SUB> (r=-0.63, p<0.05) . These results suggest that there are gender differences in intramyocellular and extramyocellular triglyceride contents. Lipids were positively related to percent body fat in SQL and MG; EMCL values may have a negative effect on endurance capacity.