CD38 and obesity due to melanocortin 4 receptor deficiency: Our results showed that the expressions of all these genes were significantly attenuated in CD38−/− mice fed with HFD compared with those of WT mice, suggesting that the protection of CD38 deficiency on obesity may be associated with inhibitions of adipocyte differentiation through repressing the expressions of PPARγ and C/EBPα in adipose tissues.