Cellular localisation of insulin-like growth factor binding protein-2 (IGFBP-2) during development of the marine fish, Sparus aurata

The spatial localisation of insulin-like growth-factor-binding protein-2 (IGFBP-2) and its mRNA was investigated during larval and post-larval developmental stages of the gilthead seabream ( Sparus aurata) by immunohistochemistry and in situ hybridisation with specific antisera and riboprobes. During larval development, immunoreactivity was found in skin, muscle, gills, pharynx, intestine, liver and olfactory epithelium. After metamorphosis, immunoreactivity was found in the oesophageal epithelium (the strongest reaction) and in red skeletal muscle, heart muscle, the thymus and the epithelium of renal tubules. In the adult, immunostaining with IGFBP-2 antibody was also found in the saccus vasculosus, ovary and testis. IGFBP-2 mRNA was detected by in situ hybridisation mainly in the intestine, skeletal musculature and ovary. These results show that IGFBP-2 protein and mRNA are expressed in a variety of seabream tissues, suggesting that IGFBP-2 regulates the actions of IGFs on these tissues during development and growth.