First report on leptin in cartilaginous fish

Leptin is a hormone involved in food intake. It is conserved through evolution, but no studies that have focused on its presence in cartilaginous fish are available to date. Here we report the presence of leptin-like immunoreactivity in the gut of the cartilaginous fish Scyliorhinus canicula (Linnaeus,1758) using Western Blot and immunohistochemical analyses. A 16 kDa band, corresponding to leptin, was detected in the homogenate of the stomach, while no immunoreactivity was observed in the intestine. Immunohistochemistry of the gastric mucosa revealed leptin-like staining localized to mucous-secreting cells and endocrine cells. This is the first report on the presence of a leptin-like peptide in a cartilaginous fish