NOS3 and obesity due to melanocortin 4 receptor deficiency: Aortic protein expression levels of MLCK, endothelial nitric oxide synthase (eNOS), and phosphorylated myosin light chain (p-MLC) were analyzed by Western blotting.<h4>Results</h4>HFD-fed rabbits developed obesity (body weight +27.85% vs. control), dyslipidemia (elevated TC, LDL-C, and ox-LDL; all <i>P</i> < 0.001), hyperglycemia (<i>P</i> < 0.05), and significant endothelial dysfunction, characterized by impaired FMD (<i>P</i> < 0.05) and reduced ACh-induced relaxation of aortic rings.