Elucidating the central anorexigenic mechanism of glucagon-like peptide 1 in Japanese quail (Coturnix japonica).

Glucagon-like peptide 1 (GLP-1) elicits a potent reduction in food intake, although the central mechanism mediating this appetite-suppressive effect is not fully understood in all species. To begin to elucidate the molecular mechanisms in quail, we administered GLP-1 via intracerebroventricular (ICV) injection to 7-day-old Japanese quail (Coturnix japonica) and determined effects on food and water intake, behavior, and brain nucleus activation. We observed a reduction in food and water intake, with the lowest effective dose being 0.01 nmol. Quail injected with GLP-1 displayed fewer steps, feeding pecks, exploratory pecks, and jumps, while time spent sitting increased. We quantified c-Fos immunoreactivity at 60 min post-injection in hypothalamic and brainstem nuclei that mediate food intake and determined that the hypothalamic paraventricular nucleus (PVN), and nucleus of the solitary tract and area postrema of the brainstem were activated in response to GLP-1. In conclusion, these results suggest that GLP-1 induces anorexigenic effects that are likely mediated at the level of the PVN and brainstem.