[Inhibition of growth hormone secretion by theophylline in asthmatic children]

Children suffering from asthma display a tendency to retarded growth and development, which also includes bone structure. The reason for this phenomenon has not been clarified. There seems to be an adaptative regulatory hypersomatotropism which can be regarded as a disturbance of peripheral growth hormone activity. We studied the question whether this is influenced by theophylline, a preparation often used in the treatment of asthma, since theophylline has been accused of growth hormone inhibition as a result of in vivo studies in adults. In 9 prepubertal boys suffering from atopic asthma we determined the growth hormone concentrations during 24 hours each before and during intravenous administration of theophylline. With this dosage the median values of the 24-hour profile (10.3 +/- 1.5 to 5.2 +/- 0.9 ng/ml), the 8-hour sleep phase (12.7 +/- 1.9 to 5.7 +/- 1.0 ng/ml) and of the maximal growth hormone peak (38.9 +/- 7.0 to 17.6 +/- 2.8 ng/ml) were significantly lower than on the first day on which theophylline was not administered. The multiple possibilities by which theophylline may be exercising this effect, are discussed. Prospective long-term clinical studies will have to clarify whether the effect is clinically significant.