BDNF and obesity due to melanocortin 4 receptor deficiency: BDNF is thought to act as an anorectic factor: like PACAP, infusions of BDNF into the lateral ventricles lead to a reduction in food intake and a number of BDNF mutant mouse models have demonstrated obesity phenotypes (Pelleymounter et al. 1995; Kernie et al. 2000; Rios et al. 2001).