Effect of two β2-agonist drugs, salbutamol and broxaterol, on the growth hormone response to exercise in adult patients with asthmatic bronchitis

Abstract

The aim of our study was to evaluate the effect of the iv administration of two different beta 2- receptors agonists, salbutamol and broxaterol, on the growth hormone (GH) response to maximal exercise in 11 patients (8 males and 3 females; age range 18-65 yr; mean +/- SE age 56 +/- 13 yr; BMI 26.2 +/- 1.4 kg/m2) with chronic asthmatic bronchitis. All the subjects underwent four cycloergometric exercise tests (incremental workload until maximal predicted heart rate). At baseline, at maximal exercise, at the end of the recovery period and 60 min after the end of each exercise, blood samples were drawn for the assay of GH, glucose, insulin, lactates, norepinephrine and epinephrine. Two exercises were performed without treatment while the remaining two were performed 60 min after the administration of 400 micrograms of either salbutamol or broxaterol (both diluted in 10 ml of saline) according to a randomized double blind cross-over design. Both exercise tests performed without treatment caused a significant (p < 0.05) and similar GH peak with respect to baseline values (from 0.3 +/- 0.1 micrograms/L to 2.8 +/- 1.3 micrograms/L, mean of the two exercise tests). Salbutamol pretreatment blunted the GH response to exercise which caused a no more significant serum GH peak over the baseline levels (from 0.6 +/- 0.2 micrograms/L to 1.4 +/- 0.6 micrograms/L,). Moreover, broxaterol completely abolished the GH response to exercise (baseline level 0.6 +/- 0.2 micrograms/L; peak levels 0.4 +/- 0.1 micrograms/L). The serum GH peak after exercise + broxaterol was significantly (p < 0.05) lower as compared to exercise + salbutamol. In conclusion, we have demonstrated for the first time that beta 2 stimulation blunts the physiological GH response to maximal exercise in adult human subjects. It can be suggested that changes in brain neurotransmitters, possibly an increase in the alpha-adrenergic tone, are likely to be involved in this endocrine effects of exercise.

Effects of Acute Salbutamol Intake During a Wingate Test

“…We did not find any significant change in basal and endexercise GH secretion between the two treatments but recovery GH appeared markedly blunted by SAL intake. This finding appears in agreement with preceding study describing decrease GH concentration after oral salbutamol intake after both maximal exercise in adult patients with asthmatic bronchitis [4] and submaximal exercise in healthy athletes [3]. It may be suggested that SAL may decrease GH secretion through hypothalamic somatostatin stimulation [4].…”

“…Similarly, hyperglycaemia and hyperinsulinaemia have often been reported as being associated with the acute use of β-adrenergic agonists [15,20]. Studies on humans also indicate that salbutamol modifies exercise GH secretion both in patients with asthmatic bronchitis and in healthy athletes [3,4].…”

Salbutamol intake and substrate oxidation during submaximal exercise

“…The earlier limited data on the effects of acute salbutamol on GH in humans (Giustina et al 1995;Collomp et al 2005;Le Panse et al 2006) have found acute salbutamol administration to decrease exercise GH concentrations, probably via enhanced somatostatin secretion and/or activity. In healthy subjects, acute b 2 stimulation blunts the physiological GH response to both maximal (Collomp et al 2002) and supramaximal exercise (Le Panse et al 2007).…”

Effects of acute salbutamol intake during supramaximal exercise in women

“…24 Sal (trade name: SALBUMOL 2 mg, tablet, Glaxo-Wellcome Laboratory, Paris, France) was administered 3 h before the test, when maximal pharmacological activity was expected.…”