BRS3 and obesity due to melanocortin 4 receptor deficiency: Although the physiological function of BRS‐3 remains unclear, BRS‐3‐deficient (Brs‐3‐/Y) mice are known to develop obesity and have a reduced metabolic rate and increased food intake (FI) (Guan et al., 2010; Ladenheim et al., 2008; Ohki‐Hamazaki et al., 1997; Yamada, Santo‐Yamada, Wada, & Wada, 2002).