Glucagon and GLP-1 inhibit food intake and increase c-fos expression in similar appetite regulating centres in the brainstem and amygdala

• Published in: International Journal of Obesity Vol. 37; no. 10; pp. 1391 - 1398
• Main Authors: Parker, J A, McCullough, K A, Field, B C T, Minnion, J S, Martin, N M, Ghatei, M A, Bloom, S R
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01.10.2013; Nature Publishing Group
• Subjects: 631/154/436/1729; 631/378/1457/1284; 631/378/2617/1346; 631/443/319/1488/393; Amygdala (Brain); Amygdala - metabolism; Animals; Appetite; Appetite - drug effects; Appetite - physiology; Biological and medical sciences; Blood; Brain Stem - metabolism; Diabetes; Dose-Response Relationship, Drug; Drug dosages; Eating (Physiology); Eating - drug effects; Energy Metabolism; Epidemiology; Food; Glucagon; Glucagon - metabolism; Glucagon - pharmacology; Glucagon-Like Peptide 1 - metabolism; Glucagon-Like Peptide 1 - pharmacology; Glucose; Health aspects; Health Promotion and Disease Prevention; Hormones; Hypothalamus; Injections, Intraperitoneal; Internal Medicine; Male; Medical sciences; Medicine; Medicine & Public Health; Metabolic Diseases; Mice; Obesity; original-article; Peptides; Physiological aspects; Proto-Oncogene Proteins c-fos - drug effects; Proto-Oncogene Proteins c-fos - metabolism; Psychological aspects; Public Health; Weight control; Weight loss; United Kingdom; United Kingdom > UK; amygdala; brainstem; appetite; GLP-1; Glucagon; food intake; Appetite; Obesity; Pancreatic hormone; Amygdala; Nutrition; Brain stem; Hyperglycemic substances; Peptide hormone; Central nervous system; Nutrition disorder; Metabolic diseases; Increase; Gene expression; Encephalon; Glucagon like peptide 1; Gastrointestinal hormone; Food intake; C-Onc gene; Nutritional status
• ISSN: 0307-0565; 1476-5497
• DOI: 10.1038/ijo.2012.227

Background: Glucagon and glucagon-like peptide-1 (GLP-1) are evolutionarily related anorectic hormones. Glucagon also increases energy expenditure. The combination of glucagon and GLP-1 could cause weight loss through a simultaneous reduction in food intake and increased energy expenditure. However, the effect of combined administration of glucagon and GLP-1 on food intake and neuronal activation has not previously been studied. Furthermore, the effect of glucagon on neuronal activation in appetite regulating centres has not been assessed. Characterisation of the effects of glucagon when administered singly and in combination with GLP-1 on neuronal activation will be important for determining the mechanism of action of related potential antiobesity therapies. Objectives: To investigate the effects of peripherally administered GLP-1 and glucagon on food intake, neuronal activation and blood glucose in mice when administered individually and in combination. Methodology: Food intake, blood glucose and c-fos expression in the hypothalamus, amygdala and brainstem were measured in response to GLP-1 and glucagon, alone and in combination. Results: Peripherally administered GLP-1 and glucagon decreased food intake and increased c-fos expression in the brainstem and amygdala. Doses of GLP-1 and glucagon that individually did not significantly affect feeding, in combination were anorectic and stimulated neuronal activation in the area postrema (AP) and central nucleus of the amygdala. Combined administration of GLP-1 and glucagon prevented the acute hyperglycemic effect of glucagon alone. Conclusion: Anorectic doses of glucagon and GLP-1 induced similar patterns of c-fos expression. Combined administration of low dose GLP-1 and glucagon inhibited food intake and induced c-fos expression in the AP and amygdala. The combination of both hormones may offer the opportunity to utilise the beneficial effects of reduced food intake and increased energy expenditure, and may therefore be a potential treatment for obesity.