MAMMALIAN GONADOTROPIN-RELEASING-HORMONE (GNRH) IDENTIFIED BY PRIMARYSTRUCTURE IN RUSSIAN STURGEON, ACIPENSER GUELDENSTAEDTI

The mammalian form of gonadotropin-releasing hormone (GnRH) was purifi ed from the brains of Russian sturgeon, Acipenser gueldenstaedti, usin g reversed-phase high pressure liquid chromatography (HPLC). The total concentration of mGnRH within these fish was 5.4 ng/brain. Small amou nts of immunoreactive chicken GnRH-II like molecules were also detecte d but at insufficient quantities for purification, The primary structu re of mGnRH was determined using automated Edman degradation. Because sequence data could not be obtained until after digestion by bovine py roglutamyl aminopeptidase, it was determined that the amino-terminal r esidue was modified. Furthermore, mass spectrometric data and co-eluti on with synthetic mGnRH on HPLC confirmed that the carboxy-terminal re sidue was amidated. The amino acid sequence of sturgeon GnRH is pGlu-H is-Trp-Ser-Tyr-Gly-Leu-Arg-Pro-Gly-NH2.