Effect of Intraparaventricular Administration of Corticotropin Releasing Hormone on Food Intake in Food-Deprived Rats

Abstract

Background: Corticotropin-releasing hormone (CRH) plays an important role on food intake regulation in the central nervous system. The CRH receptors are distributed within the hypothalamus. According to some studies, acute administration of CRH into the hypothalamic paraventricular nucleus (PVN) reduces appetite and food intake. Therefore, according to the importance of the PVN on food intake regulation and existence of CRH receptors in PVN, this study was designed to find the effect of consecutive administration of CRH into the PVN on food intake in food-deprived rats. Methods: Eighteen male Wistar rats (200-250 g) were selected in three experimental groups including control, sham and intraparaventricular-CRH-treated groups. The CRH (2 µg/kg) was administrated intraparaventricular for 7 days. At the end, food intake was measured for three continuous hours after 16-18 hour of food deprivation period. Findings: Repeated administration of CRH at the first, second, and third hours increased food intake in the CRH-treated group compared to the control group. However, at the second hour, this enhancement was significant (P < 0.01). In addition, cumulative food intake (3-hour consumption) had a significant (P < 0.01) increase in the CRH-treated group when compared to control group. Conclusion: It seems that in contrast to acute injection of CRH, repeated administration of CRH acts like stressful condition resulting in hypothalamic-pituitary-adrenal axis activation and subsequently in increased food intake.

Keywords

• Corticotropin-releasing hormone
• Paraventricular nucleus
• Food intake
• Rat