Interleukin-1 beta-induced anorexia is reversed by ghrelin

Interleukins, in particular interleukin-1β (IL-1β), reduce food intake after peripheral and central administration, which suggests that they contribute to anorexia during various infectious, neoplastic, and autoimmune diseases. On the other hand, ghrelin stimulates food intake by acting on the central nervous system (CNS) and is considered an important regulator of food intake in both rodents and humans. In the present study, we investigated if ghrelin could reverse IL-1β-induced anorexia. Intracerebroventricular (i.c.v.) injection of 15, 30 or 45 ng/μl of IL-1β caused significant suppression of food intake in 20 h fasting animals. This effect lasted for a 24 h period. Ghrelin (0.15 nmol or 1.5 nmol/μl) produced a significant increase in cumulative food intake in normally fed animals. However, it did not alter food intake in 20 h fasting animals. Central administration of ghrelin reduced the anorexic effect of IL-1β (15 ng/μl). The effect was observed 30 min after injection and lasted for the next 24 h. This study provides evidence that ghrelin is an orexigenic peptide capable of antagonizing IL-1β-induced anorexia.