Electrical stimulation-induced changes in skeletal muscle enzymes of men and women.
The purpose of the present study was to determine the effects of low-frequency electrical stimulation (LFES) on the skeletal muscle metabolic profile of men and women. The knee extensor muscles of sedentary men (N = 16) and women (N = 10) were submitted to 3 h.d-1 of 8-Hz neuromuscular electrical stimulation with the use of a portable stimulator (Respond II, Medtronic), 6 d.wk-1 for 6 wk. Enzyme activity levels of creatine kinase (CK), hexokinase (HK), glyceraldehydephosphate dehydrogenase (GAPDH), 3-hydroxyacyl CoA dehydrogenase (HADH), citrate synthase (CS), phosphofructokinase (PFK), and cytochrome c oxidase (COX) were determined in vastus lateralis muscle samples taken before and after the LFES protocol. The analyses of variance revealed no change in CK and in GAPDH. However, a small decrease in PFK activity, the rate-limiting enzyme of glycolysis, was observed in female (8%) and in male subjects (10%), but it reached significance in males only (P < 0.05). The activity level of HK, a regulatory enzyme of the skeletal muscle glucose phosphorylation (HK), increased significantly in female subjects only (36%; P < 0.01) in response to the stimulation protocol. Activity level of marker enzymes of the Krebs cycle (CS) and of the electron-transfert chain (COX) significantly increased in males (18% and 16%; P < 0.05) as well as in females (31% and 19%; P < 0.05). Increment in the marker enzyme activity of the fatty acid oxidation (HADH) was significant in female subjects (30%; P < 0.01) and, although significant, rather modest in male subjects (12%; P < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)
Gauthier
J M
JM
Physical Activity Sciences Laboratory, Laval University, Ste-Foy, Québec, Canada.
Thériault
R
R
Thériault
G
G
Gélinas
Y
Y
Simoneau
J A
JA
D000328:Adult; D001707:Biopsy, Needle; D002950:Citrate (si)-Synthase / Q000378:metabolism; D004558:Electric Stimulation; D005260:Female; D006801:Humans; D007717:Knee; D008297:Male; D009132:Muscles / Q000166:cytology / Q000201:enzymology*; D010088:Oxidoreductases / Q000378:metabolism; D010770:Phosphotransferases / Q000378:metabolism
D010088:Oxidoreductases; D002950:Citrate (si)-Synthase; D010770:Phosphotransferases