Intracerebroventricular injection of apelin-13 reduces food intake in the rat.

Apelin is a peptide recently identified as a ligand for the APJ receptor, a receptor located in tissues such as the small intestine and in the hypothalamus. Apelin has been detected in adipose tissue, gastrointestinal tract, heart and stomach. Recent reports suggest a role for apelin in the regulation of blood pressure and the control of body fluid homeostasis. The present studies examined the consequences on food intake of intravenous (IV) and intracerebroventricular (ICV) injection of apelin-13 in the Wistar rat. IV injection of 10 nmol of apelin-13 did not cause any change in food intake in either fed or 24-h fasted rats. ICV injection of 1 and 3 nmol of apelin-13 resulted in a reduction in food intake in both fed and fasted rats. The earliest reduction in food intake occurred at 4 h post-injection in fed rats. In fasted rats, food intake was reduced at 24-h post-injection only. These data provide evidence of a possible role for apelin-13 in the control of food intake.