Short- and long-term effect of oral salbutamol on growth hormone secretion in prepubertal asthmatic children

Salbutamol, a β₂-adrenergic agonist, is being extensively used in Venezuela as a brochodilator in the treatment of asthma in children. Previous reports have shown oral salbutamol either to inhibit or not to affect growth hormone (GH) secretion. We evaluated the effect of oral salbutamol (0.1 mg/kg every 6 hours for 3 months) on GH secretion in eight prepubertal short children with mild asthma. Levels of GH during sleep (samples taken every 30 minutes from 9 pm to 6 am) and after GH-releasing hormone ([GHRH] 1 μg/kg intravenously [IV]) were measured before, at 24 hours, and at 3 months of salbutamol treatment. Overnight integrated concentrations of GH and peak GH levels following GHRH diminished significantly after 24 hours of salbutamol therapy (from 4.5 ± 1.3 to 3.4 ± 0.8 μg/L and from 46.6 ± 47.3 to 16.2 ± 7.9 μg/L, respectively, P < .05). However, GH levels after 3 months of salbutamol were not different from basal levels (4.5 ± 1.3 v 5.1 ± 5.1 ± 2.9 μg/L during the overnight studies and 46.6 ± 47.3 v 37.8 ± 30.4 μg/L after GHRH). Our data suggest an inhibition of both spontaneous and stimulated GH secretion following short-term oral salbutamol ingestion, but this suppressive effect is not maintained with its long-term use.