In genetically obese (db/db) and diet-induced obese C57BL/6J (B6) mice, nicotine (400 μg/kg, i.p. t.i.d) suppressed obesity-induced inflammation by normalizing the elevated expression of F4/80 and pro-inflammatory cytokines, including TNF-α, IL-6, IL-1β, and iNOS, and reduced the expression of MCP1 in adipose tissue or TNF-α in serum (148). This evidence concerns the gene TNF and obesity due to melanocortin 4 receptor deficiency.