Resistin (FIZZ3; ADSF) has a relative mass of 12kDa and belongs to a family of cysteine-rich C-terminal domain secreted proteins, known as resistin-like molecules (RELMs) or “found in the inflammatory zone” (FIZZ) proteins. It was discovered by three different groups which reported resistin to be a transcript suppressed by antidiabetic thiazolidinediones, a secretory product of adipose tissue and a homolog of proinflammatory proteins. As with adiponectin, different multimeric forms of circulating resistin have been identified. In rodents, increased resistin-levels have been shown to impair insulin action, while genetic ablation or downregulation of the resistin gene improves insulin sensitivity. In contrast to rodents, the role and sites of synthesis of human resistin are controversially discussed. Only a minority of reports have demonstrated human resistin expression in adipocytes, while most reports identified inflammatore cells and bone marrow-derived as the main source, indicating a role in inflammatory responses.
