Contrasting effects of No on food intake and Gh secretion stimulated by a Gh releasing peptides (GHRP) in youg rats

Objective. Based on NO involvement in the GH-releasing effect of the GH-releasing peptides (GHRP s) and the reported orexigenic activity of these compounds, we sought to evaluate the effect of the combined administration of a long-acting NO-donor, molsidomine, and/or an inhibitor of NO-synthase, N-nitro-arginine-methyl-ester (NAME). and the GHRP EP92632 on food-intake and GH secretion in rats. Methods, In the food-intake experiments, adult Sprague-Dawley male rats underwent acute administration of: 1) EP92632 (160 ~g/kg , sc): 2) molsidomine (100mg/kg, ip): 3) EP92632+ molsidomine; 4) L-NAME (60mg/kg, ip); 5) EP92632 + L-NAME (60mg/kg, ip): 6) EP92632+ molsidomine+L-NAME (60mg/kg, ip): 7)0.9%saline(0.1ml/kg, ip). Inthe neuroendocrine experiments, rats were given the same cempounds accerding to the above reported schedule, except for the use of a lower EP92632 dose (80 ~ g/kg, sc). Results. EP92632 significantly stimulated food-intake (3A±0.6 vs. 2,6±0.7g, P<0.01), an effect which was further enhanced by molsidomine (6.4±0.6g. P