Effects of sex hormones on bronchial reactivity during the menstrual cycle

Background: Perimenstrual asthma(PMA) is defined as the exacerbation of the respiratory symptoms in asthmatic premenopausal females during the premenstrual phase and/or the first days of menstruation. We studied the effect of the menstrual cycle on bronchial reactivity(BR) in a group of women with PMA. Methods: 36 pre-menopausal women underwent testing for resting pulmonary function, measurement of the diffusing lung capacity for carbon monoxide(DLCO), and airway responsiveness to methacholine in the follicular and luteal phases of their menstrual cycles. We also measured circulating levels of prolactin, follicle-stimulating hormone, luteinizing hormone, testosterone, progesterone and 17β-estradiol in plasma, and levels of cyclic adenosine monophosphate(cAMP) which is a mediator of bronchial smooth muscle contraction, and testosterone in induced sputum. Results: About 70% of the women with asthma had increased BR in the follicular phase of the menstrual cycle, and there was a significant correlation between BR and serum testosterone levels. Moreover, we observed a marked increase in sputum testosterone levels and cAMP concentration during the luteal phase of the menstrual cycle in the PMA patients. We excluded a direct effect of testosterone on inhibiting PDE activity as incubating PDE with testosterone in vitro did not reduce PDE catalytic activity. Conclusions: BR is increased in the follicular phase of the menstrual cycle of premenopausal women, and was also associated with lower testosterone and cAMP levels in sputum samples which may contribute to bronchoconstriction. Targeting testosterone and/or cAMP in patients with PMA could improve the management of the asthma symptoms during the menstrual cycle.