TNF-alpha (TNF-α) produces different effects as it is secreted; many of these effects are immunological and result in increased inflammation. The original name for TNF, tumor necrosis factor, came from its first discovered activity, tumor regression. TNF-α is synthesized and secreted by adipocytes, macrophages, lymphoid cells, endothelial cells and other body cells.
Adipocyte-secreted TNF-α stimulates adipocytes to increase their release of NEFAs and decrease adiponectin synthesis. TNF-α also inhibits insulin activity, leading to insulin resistance. Adipocyte TNF-α secretion is increased in obesity causing an increased insulin resistance in obesity.