GRN and obesity due to melanocortin 4 receptor deficiency: Similarly, insulin resistance, adipocyte hypertrophy and obesity result from perturbations in the regulation of the inflammatory cytokines interleukin 6 (IL-6) and tumor necrosis factor α (TNF-α) in mice with increased PGRN through Pgrn over-expression or administration of recombinant PGRN [93, 95, 107, 196].