PVN galanin increases fat storage and promotes obesity by causing muscle to utilize carbohydrate more than fat

• Published in: Peptides (New York, N.Y. : 1980) Vol. 26; no. 11; pp. 2265 - 2273
• Main Authors: Yun, R., Dourmashkin, J.T., Hill, J., Gayles, E.C., Fried, S.K., Leibowitz, S.F.
• Format: Journal Article
• Language: English
• Published: New York, NY Elsevier Inc 01-11-2005; Elsevier Science
• Subjects: 3-Hydroxyacyl CoA Dehydrogenases - metabolism; Adipose Tissue - enzymology; Animals; Biological and medical sciences; Blood Glucose - metabolism; Carbohydrate metabolism; Dietary fat; Eating behavior; Enzyme Activation - drug effects; Fatty Acids - blood; Fundamental and applied biological sciences. Psychology; Galanin; Galanin - administration & dosage; Lipoprotein Lipase - metabolism; Male; Medical sciences; Metabolic diseases; Muscle, Skeletal - enzymology; Obesity; Obesity - chemically induced; Obesity - metabolism; Oxidation-Reduction - drug effects; Paraventricular nucleus; Phosphofructokinases - metabolism; Rats; Rats, Sprague-Dawley; Vertebrates: endocrinology; Dietary fat; Obesity; Carbohydrate metabolism; Paraventricular nucleus; Galanin; Eating behavior; Feeding behavior; Central nervous system; Nutrition disorder; Metabolism; Neuropeptide; Encephalon; Storage; Carbohydrate; Muscle; Nutritional status
• ISSN: 0196-9781; 1873-5169
• DOI: 10.1016/j.peptides.2005.04.005

To understand the function of the feeding-stimulatory peptide, galanin (GAL), in eating and body weight regulation, the present experiments tested the effects of both acute and chronic injections of this peptide into the paraventricular nucleus (PVN) of rats. With food absent during the test, acute injection of GAL (300
pmol/0.3
μl) significantly increased phosphofructokinase activity in muscle, suggesting enhanced capacity to metabolize carbohydrate, and reduced circulating glucose levels. It also decreased β-hydroxyacyl-CoA dehydrogenase activity in muscle, indicating reduced fat oxidation, while increasing circulating non-esterified fatty acids (NEFA) and lipoprotein lipase activity in adipose tissue (aLPL). Chronic PVN injections of GAL (300
pmol/0.3
μl/injection) versus saline over 7–10 days significantly stimulated daily caloric intake and increased the weight of four dissected fat depots by 30–40%. These effects, accompanied by elevated levels of leptin, triglycerides, NEFA and aLPL activity, were evident only in rats on a diet with at least 35% fat. Thus, by favoring carbohydrate over fat metabolism in muscle and reversing hyperglycemia, PVN GAL may have a function in counteracting the metabolic disturbances induced by a high-fat diet. As a consequence of these actions, GAL can promote the partitioning of lipids away from oxidation in muscle towards storage in adipose tissue.