TNF and infectious disease: Although fever is characteristic of infectious diseases, several peptides, such as interleukins 1 and 6 and tumor necrosis factor, also act on the posterior hypothalamus, inducing prostaglandin production in the hypothalamic endothelium and pineal region, activated by the systemic release of peptides from the appendix, resulting in increased temperature as they act on the hypothalamic temperature-regulating center [[48], [49], [50], [51], [52]].