TNF and obesity due to melanocortin 4 receptor deficiency: In our previous study, GHP could reduce the levels of interleukin-6 (IL-6), interleukin-1 beta (IL-1β) and tumor necrosis factor-alpha (TNF-α) in macrophages via Akt mediated nuclear factor-κB (NF-κB) signaling [19], and reduced pro-inflammatory cytokines in HFD-induced obesity rats [20], suggesting that GHP may have benefits on gut microbiota.