NOS3 and obesity due to melanocortin 4 receptor deficiency: Because of the established links of bile acid signaling on energy expenditure (Watanabe et al., 2006), lipid and glucose homeostasis (Watanabe et al., 2004; Zhang et al., 2006), and obesity (Watanabe et al., 2006, 2011), we reasoned that changes in the bile acid pathway could be important for the hypermetabolic and anti-obesogenic effects of eNOS.