Oral administration of ipamorelin, a peptidic growth hormone secretagogue, in adult beagles

This study evaluated the efficacy of oral ipamorelin administration in adult beagle dogs, an innovative approach considering that most peptidic GH secretagogues require parenteral administration. The researchers treated the animals with oral ipamorelin for 12 weeks and monitored body composition and bone metabolism parameters.

The results demonstrated that oral ipamorelin was able to stimulate GH release significantly, even after passage through the gastrointestinal tract. The observed anabolic effects included:

• Increase in lean body mass
• Increase in bone mineral density
• Elevation of circulating IGF-I levels

A notable finding was that these anabolic effects occurred without significant increase in total body weight, suggesting an improvement in body composition (more muscle, less fat) rather than simple mass gain. Cortisol and prolactin profiles remained stable, confirming the selectivity of ipamorelin observed in the study by Raun et al. (1998).

Although oral bioavailability of peptides is generally low, this study demonstrated that ipamorelin can be effective via the oral route at adequate doses, opening perspectives for non-injectable formulations. The effects on bone density are particularly relevant for potential applications in osteoporosis and sarcopenia.