[Atrial natriuretic factor (ANF) and chronic obstructive bronchopneumonia (COBP): the effects of theophylline treatment].

We have considered the behaviour of the atrial natriuretic factor (ANF) in eight patients suffering from chronic obstructive pulmonary disease (COPD), who have been treated with aminophylline for 24 hours. The mean of ANF concentration decreased from a basic value of 171.31 pg/ml to a value of 128.83 pg/ml (p: n.s.) after treatment. With the exception of patient n. 5 and 7, in the remaining group a significant inverse correlation between ANF and aldosterone was found in accordance with the powerful inhibitory action exerted by the ANF on the secretion of the mineralocorticoid hormone. The changes of the ANF, after a treatment with aminophylline, are characterized by considerable differences among the several patients. In all patients who had a very high basic value, we generally assist to a plasmatic concentration reduction of the hormone after methylxantine. It can be assumed that the reduction of the pulmonary arterial pressure owing to the direct vessel-dilating action of the methylxantine as well as to the effect of vein-dilating and diuretic action reduce the stimulus to the secretion of ANF.