NPY and obesity due to melanocortin 4 receptor deficiency: These mice exhibited hyperphagia and obesity along with increased hypothalamic gene expression of agouti-related neuropeptide (Agrp), but without significant effect on neuropeptide Y (Npy), proopiomelanocortin (Pomc) or cocaine and amphetamine regulated transcript (CART) prepropeptide (Cartpt)12.