On the other hand, although oxytocin receptor‐deficient male mice show late‐onset mild obesity,166 it has been reported that oxytocin receptor deficiency,166 chemogenetic inhibition of hypothalamic paraventricular oxytocin neurones,167 genetically targeted ablation of oxytocin neurones152 and destruction of hypothalamic paraventricular oxytocin neurones150 do not significantly change the total amounts of food intake in mice. This evidence concerns the gene OXTR and obesity due to melanocortin 4 receptor deficiency.