Glucose metabolism and metabolic flexibility in cultured skeletal muscle cells is related to exercise status in young male subjects

Abstract

We hypothesised that skeletal muscles of healthy young people have a large variation in oxidative capacity and fibre-type composition, and aimed therefore to investigate glucose metabolism in biopsies and myotubes isolated from musculus vastus lateralis from healthy males with varying degrees of maximal oxygen uptake. Trained and intermediary trained subjects showed higher carbohydrate oxidation in vivo. Fibre-type distribution in biopsies and myotubes did not differ between groups. There was no correlation between fibre-type I expression in biopsies and myotubes. Myotubes from trained had higher deoxyglucose accumulation and fractional glucose oxidation (glucose oxidation relative to glucose uptake), and were also more sensitive to the suppressive action of acutely added oleic acid to the cells. Despite lack of correlation of fibre types between skeletal muscle biopsies and cultured cells, myotubes from trained subjects retained some of their phenotypes in vitro with respect to enhanced glucose metabolism and metabolic flexibility.

Higher lipid turnover and oxidation in cultured human myotubes from athletic versus sedentary young male subjects

“…Selected donor characteristics are presented in Table 1 , and have been presented in full previously 18 . As expected the athletic subjects performed at a higher workload max and they also had higher maximal fat oxidation in vivo , as determined during an incremental test, compared to sedentary subjects (Table 1 ).…”

“…BMI, body mass index; VO 2max , maximal oxygen uptake; WHR, waist-to-hip ratio. Complete set of donor characteristics have been reported in full previously 18 .…”

“…We have previously described, using cultured skeletal muscle cells from the same athletic (maximal oxygen uptake, VO 2max > 60 ml/kg/min) and sedentary (VO 2max ≤ 46 ml/kg/min) subjects as in the current work, that myotubes from athletic subjects showed higher deoxyglucose accumulation and fractional glucose oxidation. Further, myotubes from athletic donors were also more sensitive to the suppressive action of acutely added oleic acid to the cells 18 .…”

Metabolic Responses to Carbohydrate Ingestion during Exercise: Associations between Carbohydrate Dose and Endurance Performance

“…With longer task durations (>3 h) an increased reliance on exogenous CHO oxidation later in exercise could enhance liver glycogen sparing and could improve subsequent performance outcomes. Furthermore, with improved training status comes improved capacity to oxidize substrates [ 20 , 21 ] which might drive the CHO provision threshold beyond 40–60 g·h −1 .…”

Treatment of human skeletal muscle cells with inhibitors of diacylglycerol acyltransferases 1 and 2 to explore isozyme-specific roles on lipid metabolism

“…Donors were 25.5 (±0.95) (mean ± SEM) years old with a body mass index of 22.1 (±0.8) kg/m 2 . More details about the donor cohort used in this study, as well as characteristics of myotubes can be found in the study by Lund et al 28 . Muscle biopsies were obtained after informed written consent and approval by the National Committee for Research Ethics, Oslo, Norway (2011/2207 REK South East B).…”