Intracerebroventricular administration of mouse leptin does not reduce food intake in the chicken

Recently, it has been suggested that leptin plays an important role in regu lation of food intake and metabolism in rats and mice, however, the effect of central administration of leptin on food intake in chicks has not been r eported. We have investigated the anorexigenic effect of leptin administere d by intracerebroventricular (i.c.v.) injection in chicks using mouse lepti n, which shows 97% homology to chicken leptin. Three experiments were condu cted. After being deprived of food for 3 h, male broiler chicks were admini stered leptin by i.c.v. injection at dose levels of 0, 0.2, 1.0 and 5.0 mu g (Experiment 1) or 0, 2.5 and 5.0 pg (Experiment 2). The birds were allowe d free access to the diet for 2 h (Experiment 1) and 24 h (Experiment 2) af ter treatment. Male Single Comb White Leghorn chicks were used in Experimen t 3 and were treated in the same manner as in Experiment 1. In all experime nts, central administration of mouse leptin did not influence food intake i n the time periods examined. It appears that either mouse leptin does not b ind to the chicken leptin receptor or in the chicken brain the leptin recep tor may be absent. (C) 1999 Elsevier Science B.V.