Peak expiratory nitric oxide differences in men and women: relation to the menstrual cycle.
OBJECTIVE
To develop a method to measure end expiratory nitric oxide concentration and to use it to determine whether there are sex related differences between healthy men and women.


METHODS
Modification of commercially available chemiluminescent analyser to allow endogenous nitric oxide (endothelium derived relaxing factor) to be measured in a single slow forced vital capacity manoeuvre with evaluation of between and within subject variability. Serial measurements in women throughout the menstrual cycle.


METHODS
Specialist referral hospital.


METHODS
59 healthy volunteers (40 men and 19 women).


RESULTS
Mean (SD) peak expiratory concentrations of nitric oxide in men (75 (20) ppb (parts per billion)), and women (70 (37) ppb (first measurement)) were > 5 times those previously recorded. In women concentrations at midcycle (150(39) ppb) were significantly higher (mean difference 94.9(41), P < 0.001) than during menstruation (59(25) ppb).


CONCLUSIONS
Nitric oxide production (endothelium derived relaxing factor activity) is influenced by cyclical hormonal changes in women. There was an increase of more than 100% at mid cycle. This may be pertinent to the lower risk of cardiovascular disease in premenopausal women.
Kharitonov
S A
SA
Department of Paediatrics, Royal Brompton National Heart and Lung Hospital, London.
Logan-Sinclair
R B
RB
Busset
C M
CM
Shinebourne
E A
EA
D000328:Adult; D001944:Breath Tests; D004967:Estrogens / Q000502:physiology; D005260:Female; D006801:Humans; D008163:Luminescent Measurements; D008297:Male; D008597:Menstrual Cycle / Q000378:metabolism*; D009569:Nitric Oxide / Q000032:analysis*; D015203:Reproducibility of Results; D012119:Respiration / Q000502:physiology*; D012737:Sex Factors
D004967:Estrogens; D009569:Nitric Oxide