[Dynamic 31-phosphorus magnetic resonance spectroscopy of the m. quadriceps: the effect of sex and age on the spectroscopic parameters].
OBJECTIVE
31P-MRS is used to assess the influence of sex und age on quadriceps muscle metabolism before and after exercise.


METHODS
32 healthy volunteers (15 women, 17 men, mean age: 38 +/- 17 yrs.) were examined by dynamic phosphorus-31 (31P) magnetic resonance spectroscopy (MRS). In the magnet, the quadriceps muscle was stressed by an isometric und an isotonic form of exercise until exhaustion, respectively.


RESULTS
Resting conditions: With increasing subjects' age, the ratio beta-adenosine triphosphate/total phosphate decreased (r = -0.37; p = 0.02). With increasing subjects' age, the ratios inorganic phosphate/phosphocreatine (r = 0.79; p = 5 x 10(-8), phosphomonoester/beta-adenosine triphosphate (r = 0.74; p = 10(-6) and phosphodiester/beta-adenosine triphosphate (r = 0.62; p = 10(-4) increased. The pH was the only one of the evaluated spectroscopic parameters which showed a sex-dependence: Female subjects had a significantly lower pH (7.03 +/- 0.02) than male subjects (7.05 +/- 0.03; p = 0.01). Exercise: With increasing age, the maxima of inorganic phosphate/phosphocreatine were less extreme during both of the exercises (r = -0.42; p = 0.0005). Likewise, the exercise-induced acidosis was less severe with increasing age (r = 0.53; p = 6 x 10(-6). After the end of the exercise, the times of half recovery of inorganic phosphate/phosphocreatine and the pH correlated neither with the subjects' age nor with sex or cross-sectional areas of the quadriceps muscle.


CONCLUSIONS
Sex and age of volunteers affect spectroscopic results. This influence had to be considered in the interpretation of spectroscopic studies.
Schunk
K
K
Klinik und Poliklinik für Radiologie, Johannes Gutenberg-Universität Mainz. SCHUNK@Radiologie.Klinik.uni-mainz.de
Romaneehsen
B
B
Kessler
S
S
Schadmand-Fischer
S
S
Thelen
M
M
D000328:Adult; D000375:Aging / Q000378:metabolism*; D015444:Exercise / Q000502:physiology; D005260:Female; D006801:Humans; D007551:Isotonic Contraction / Q000502:physiology; D009682:Magnetic Resonance Spectroscopy / Q000295:instrumentation / Q000379:methods*; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000378:metabolism*; D012016:Reference Values; D012727:Sex Characteristics; D012815:Signal Processing, Computer-Assisted; D018709:Statistics, Nonparametric
Die dynamische 31-phosphor-Magnetresonanz-Spektroskopie des M. quadriceps: Einfluss von Geschlecht und Alter auf spektroskopische Parameter.