NAMPT and obesity due to melanocortin 4 receptor deficiency: One such study observed a negative association between the level of resistin in seminal fluid and sperm vitality and motility, as well as a positive association with markers of inflammation in semen like elastase and IL-6 [204]. This suggests a vital role of resistin in seminal fluid and male reproductive system inflammation [182]. The role of visfatin is unclear in obesity since certain studies have observed high concentrations of visfatin provoke insulin resistance, while other research has noted its protective role [205,206].