ARG1 and obesity due to melanocortin 4 receptor deficiency: Greater expression of hepatic ARG1 has been associated with reduction in circulating nitric oxide level, which might lead to endothelial dysfunction.29 Interestingly, compared to SHM-R, OVX-R mice display a higher (p < .05) expression of hepatic fetuin A, a marker that has been associate with obesity, type 2 diabetes, metabolic syndrome, and nonalcoholic fatty liver disease (Figure 5e).