CD36 and obesity due to melanocortin 4 receptor deficiency: Obesity is associated with oxidative stress and increased oxLDL[46, 47], therefore it is reasonable to speculate that the upregulation of macrophage CD36 may interact with oxLDLs to initiate inflammatory responses in nicotine-treated obese rats, but the similar pathway may not be activated by nicotine in lean rats because there may not have enough oxidized LDL products to stimulate CD36 inflammatory pathway in lean rats.