Expression pattern of somatolactin in the C hinese sturgeon, A cipenser sinensis G ray, 1835

Summary Somatolactin ( SL ) is a pituitary hormone specific to fish and is reported in a variety of teleost species. Although it appears to be involved in many different physiological processes, its biological functions are poorly understood in A cipenseriformes. In this paper the expression pattern of this protein is characterized in C hinese sturgeon ( A cipenser sinensis ). Structure analysis showed that A s SL had a 24aa signal peptide and a 208aa mature protein, one N ‐glycosylation site at positions 145‐147 and seven C ys residues conserved with other SL s. The antiserum was raised against a 15 aa antigen, derived from the C hinese sturgeon somatolactin ( A s SL ) amino acid sequence. Western blot analysis showed the pituitary‐specific expression of A s SL . In situ hybridization revealed that the mRNA of A s SL was expressed mainly in pars intermedia ( PI ), although also slightly in proximal pars distalis ( PPD ), cells expressing A s SL disperse throughout the pars intermedia. These findings provide useful information for future physiological research in C hinese sturgeon.