Mammalian gonadotropin-releasing hormone (GnRH) identified by primary structure in Russian sturgeon, Acipenser gueldenstaedti

Abstract The mammalian form of gonadotropin-releasing hormone (GnRH) was purified from the brains of Russian sturgeon, Acipenser gueldenstaedti , using reversed-phase high pressure liquid chromatography (HPLC). The total concentration of mGnRH within these fish was 5.4 ng/brain. Small amounts of immunoreactive chicken GnRH-II like molecules were also detected but at insufficient quantities for purification. The primary structure of mGnRH was determined using automated Edman degradation. Because sequence data could not be obtained until after digestion by bovine pyroglutamyl aminopeptidase, it was determined that the amino-terminal residue was modified. Furthermore, mass spectrometric data and co-elution with synthetic mGnRH on HPLC confirmed that the carboxy-terminal residue was amidated. The amino acid sequence of sturgeon GnRH is pGlu-His-Trp-Ser-Tyr-Gly-Leu-Arg-Pro-Gly-NH 2 .