Resistin (resistance-to-insulin), also known as adipocyte-specific secretory factor (ADSF) and found in inflammatory zone 3 (FIZZ3), is a 10 kDa member of a small family of secreted cysteine-rich peptide hormones. Human Resistin precursor is 108 amino acids (aa) in length. It contains an 18 aa signal sequence plus a 90 aa mature region. The mature region shows an N-terminal alpha -helical tail (aa 23 44) and a C-terminal beta sheet globular head (aa 47 108). Mature human Resistin shares 56% and 54% aa identity with mouse and rat Resistin, respectively. Rat Resistin possesses an alternate start site at Met48; this Met is not found in the mouse molecule, however. Although the function of Resistin is unclear, it would seem to block insulin-stimulated uptake of glucose by adipocytes and promote glucose release by hepatocytes. As such, it has been proposed to participate in dietinduced insulin-sensitivity.