Relationship between body composition and skeletal muscle eNOS.
OBJECTIVE
Owing to the relationship between nitric oxide related endothelial dysfunction, insulin resistance and cardiovascular disease in overweight individuals, we investigated if skeletal muscle endothelial nitric oxide synthase (eNOS) protein content and activity are lower in overweight than lean women.


METHODS
A total of 19 women (age 26.0+/-1.7 years) underwent a resting muscle biopsy, body composition analysis by hydrostatic weighing and peak aerobic capacity determination using indirect calorimetry (Study 1). An additional separate set of six lean (< or = 25% fat) and six overweight (>25% fat) women were subsequently studied for the determination of eNOS activity, and to better control for absolute peak aerobic capacity between lean and overweight women (Study 2).


RESULTS
Skeletal muscle eNOS content was inversely related to percent body fat (r2 = 0.58, P < 0.01), and body mass index (r2 = 0.35, P < 0.05). Total eNOS activity was lower in overweight than lean women (2.09 +/- 0.22 vs 1.44 +/- 0.17 U, P < 0.05; n = 12), and was inversely related to percent body fat (r2 = 0.32, P = 0.05), and BMI (r 2 = 0.41, P < 0.05). Absolute and relative aerobic capacity were not independent predictors of skeletal muscle eNOS content (r2 = 0.11 and 0.26, respectively).


CONCLUSIONS
There is an inverse relationship between eNOS and percent body fat that may have implications for the previously reported reduced endothelial function and insulin sensitivity in overweight women.
Hickner
R C
RC
Human Performance Laboratory, Department of Exercise and Sport Science, East Carolina University, Greenville, NC, USA. Hicknerr@mail.ecu.edu
Kemeny
G
G
Stallings
H W
HW
Manning
S M
SM
McIver
K L
KL
D000328:Adult; D001706:Biopsy; D001823:Body Composition; D002153:Calorimetry, Indirect; D016022:Case-Control Studies; D015444:Exercise; D017079:Exercise Tolerance; D005260:Female; D006801:Humans; D018482:Muscle, Skeletal / Q000201:enzymology*; D052250:Nitric Oxide Synthase Type III / Q000032:analysis / Q000378:metabolism*; D050177:Overweight / Q000502:physiology*; D012044:Regression Analysis
D052250:Nitric Oxide Synthase Type III