Endocrine Abstracts

Background: The activation of the GHS-R1a receptor by acylated ghrelin (AG) or by synthetic GH secretagogues (GHS), potently stimulates GH release and mediates other neuroendocrine/metabolic effects. Beta-adrenergic receptor agonists negatively influence GH secretion and other metabolic functions. The GH response to AG and GHS is refractory to the inhibitory effect of β2-adrenoceptors activation but no other report has evaluated the interactions between AG and salbutamol on metabolic parameters. Therefore, the present study intended to investigate insulin, glycemic and FFA values in response to a combined treatment with AG and Salb (AG/Salb).

Methods: Six healthy young male volunteers underwent the following testing sessions in random order: a) Salb (iv infusion of 0.06 μg/kg per min from 0 to 60 min), b) co-infusion of AG (1.0 μg/kg per min iv from −240 to 60 min) and Salb (0.06 μg/kg per min iv 0–60 min) and c) isotonic saline (iv infusion from 0 to 60 min). Insulin, glycemia and FFA levels were evaluated every 15 min.

Results: During the AG/Salb treatment, a significant elevation from 0 min insulin and FFA levels was observed at all time points (P<0.05). Incremental insulin AUC values were significantly higher in both AG/Salb and Salb treatments when compared to Saline (P<0.001). During AG/Salb, glycemic AUC values were increased when compared to those observed during treatments with Salb alone (P=0.02) or Saline (P=0.053). In addition, FFA AUC values were increased in AG/Salb when compared to Salb (P=0.05) and Saline treatments (P=0.005). Interestingly this effect was accentuated when incremental FFA AUC values were compared between the three treatments: AG/Salb when compared with Salb (P=0.045) and Saline (P<0.001).

Conclusion: Taken as a whole, the present study indicates that Salb and AG both exert effects on metabolism and furthermore, results strongly suggest that it could act in a synergetic manner to increase lipolysis.