Melatonin counteracts changes in hypothalamic gene expression of signals regulating feeding behavior in high-fat fed rats

RÍOS-LUGO MJ; JIMÉNEZ-ORTEGA V; CANO-BARQUILLA P; FERNÁNDEZ MATEOS P; SPINEDI E; CARDINALI DP; ESQUIFINO AI

Hormone Molecular Biology and Clinical Investigation

De Gruyter

Lugar: Berlin; Año: 2015 vol. 21 p. 175 - 183

1868-1891

Background: Previous studies indicate that the administration of melatonin caused body weight and abdominal visceral fat reductions in rodent models of hyperadiposity. The objective of the present study performed in high-fat fed rats was to evaluate the activity of melatonin on gene expression of some medial basal hypothalamus (MBH) signals involved in feeding behavior regulation, including neuropeptide Y (NPY), proopiomelanocortin (POMC), prolactin-releasing peptide (PrRP), leptin- and insulinreceptors (R) and insulin-R substrate (IRS)-1 and -2. Blood levels of leptin and adiponectin were also measured. Methods: Adult Wistar male rats were divided into four groups (n= 16/group): (i) control diet (3 % fat); (ii) high-fat (35 %) diet; (iii) high-fat diet + melatonin; (iv) control diet + melatonin. Rats had free access to high-fat or control chow and one of the following drinking solutions: (a) tap water; (b) 25 μg/mL of melatonin. Results: After 10 weeks, the high-fat fed rats showed augmented MBH mRNA levels of NPY, leptin-R, PrRP, insulin-R, IRS-1 and IRS-2. The concomitant administration of melatonin counteracted this increase. Feeding of rats with a high-fat diet augmented expression of MBH POMC gene through an effect insensitive to melatonin treatment. The augmented levels of circulating leptin and adiponectin seen in high-fat fed rats were counteracted by melatonin as was the augmented body weight: melatonin significantly attenuated body weight increase in high-fat fed rats without affecting chow or water consumption. Melatonin augmented plasma leptin and adiponectin in control rats.